What s the difference between a proxy server and a reverse proxy server

Question

What is the difference between a proxy server and a reverse proxy server

User · Answer

As per my understanding    To start with  as everyone knows  proxy means  quot the authority to represent someone else quot   Now there are two things  forward and reverse proxy  Forward proxy Suppose you want to access  quot Google quot  and  quot Google quot  in turn will have n number of servers to respond to that particular request  Now in this case  while you are requesting for something from Google and you don   t want Google to see your IP address  then you will use a forward proxy  as explained below  A   B   C Now here you are A  sending a request through B  So C will think that the request is coming from B  not A  In this way you can prevent your clients IP address not to be exposed to outer world  Reverse proxy Now in this case  to make you understand  we will take the same case of forward proxy  Here you have requested for something to Google  which in turn going to send the one request to the app server or another proxy server to get the response  So these things will happen as explained below  A    B    C C    D C    D A   B   C From the above diagram you can see that a request has been sent to C from B  not from A  Then from C there will be one request send to D  Similarly the response will go to C from D and then to B and A  The above diagram says it s only the context which matters although both the proxies are acting the same way  but the client-side proxy is hiding the client information whereas the server-side proxy will hide server-side information

User · Answer

My understanding from an Apache perspective is that proxy means that if site x proxies for site y  then requests for x return y   The reverse proxy means that the response from y is adjusted so that all references to y become x   So that the user cannot tell that a proxy is involved

User · Answer

If no proxy  To see from the client side and server side are the same   Client   -    Server  Proxy  From the client side   Client  -   proxy -  Server  From the server side   Client  -   Server  Reverse proxy  From the client side   Client  -   Server  From the server side   Client  -   proxy -  Server  So I think if it set up by a client user it is called a proxy  if it set up by a server manager it is a reverse proxy   Because the purposes and reasons for setting it up are different  they deal with data in different ways and use different software      User side                 Server side client   lt - gt   proxy   lt -- gt   reverse proxy  lt - gt  real server

User · Answer

A pair of simple definitions would be   Forward Proxy  Acting on behalf of a requestor  or service consumer   Reverse Proxy  Acting on behalf of  service content producer

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Some diagrams might help   Forward proxy    Reverse proxy

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Forward proxies grant the client anonymity  i e  think Tor    Reverse proxies grant back end servers anonymity  i e  think servers behind a DMZ

User · Answer

Let s consider the purpose of the service  In forward proxy  Proxy helps user to access server  In reverse proxy  Proxy helps server to be accessed by user  In the latter case  the one who is helped by the proxy is no longer a user  but a server  that s the reason why we call it a reverse proxy

User · Answer

The difference is primarily in deployment  Web forward and reverse proxies all have the same underlying features  They accept requests for HTTP requests in various formats and provide a response  usually by accessing the origin or contact server   Fully featured servers usually have access control  caching  and some link-mapping features   A forward proxy is a proxy that is accessed by configuring the client machine  The client needs protocol support for proxy features  redirection  proxy authentication  etc    The proxy is transparent to the user experience  but not to the application   A reverse proxy is a proxy that is deployed as a web server and behaves like a web server  with the exception that instead of locally composing the content from programs and disk  it forwards the request to an origin server  From the client perspective it is a web server  so the user experience is completely transparent   In fact  a single proxy instance can run as a forward and reverse proxy at the same time for different client populations

User · Answer

Some diagrams might help   Forward proxy    Reverse proxy

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Cloudflare has a great article with images explaining this in details       Check here    What Is A Reverse Proxy    Proxy Servers Explained

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Looking from the perspective of the user  when sending a request to a proxy or reverse proxy server    proxy - requires two arguments  1  what to get and 2  which proxy server to use an intermediate reverse proxy - requires one argument  1  what to get   A reverse proxy fetches contents from another server unbeknownst to the user and returns the result as if it originated from the reverse proxy server

User · Answer

A proxy server proxies  and optionally caches  outgoing network requests to various not-necessarily-related public resources across the Internet  A reverse proxy captures  and optionally caches  incoming requests from the Internet and distributes them to various internal private resources  usually for high availability purposes

User · Answer

If no proxy  To see from the client side and server side are the same   Client   -    Server  Proxy  From the client side   Client  -   proxy -  Server  From the server side   Client  -   Server  Reverse proxy  From the client side   Client  -   Server  From the server side   Client  -   proxy -  Server  So I think if it set up by a client user it is called a proxy  if it set up by a server manager it is a reverse proxy   Because the purposes and reasons for setting it up are different  they deal with data in different ways and use different software      User side                 Server side client   lt - gt   proxy   lt -- gt   reverse proxy  lt - gt  real server

User · Answer

My understanding from an Apache perspective is that proxy means that if site x proxies for site y  then requests for x return y   The reverse proxy means that the response from y is adjusted so that all references to y become x   So that the user cannot tell that a proxy is involved

User · Answer

Proxy  Forward Proxy    When computers on your LAN connect to a proxy server that accesses the Internet  Benefits include only the server being exposed to the Internet  People on the outside are unable to access the computers directly  Forward proxies can improve Internet access for users by caching downloads  They can also be used to restrict access to certain sites  Also  only the proxy server would need a public address  not the clients connecting to it   Reverse Proxy   A reverse proxy is the opposite of a forward proxy  Instead it acts as a proxy on behalf of the servers being connected to  Instead of accessing a remote server directly  a user would go through the reverse proxy and get directed to the appropriate  server from there  Only the reverse proxy would need an SSL certificate  only one public IP address would be needed  and it can handle load balancing of incoming requests to enhance the overall user experience      Image Source  Creating a Forward Proxy Using Application Request Routing

User · Answer

Difference between Proxy server  also called forward proxy  and Reverse Proxy Server depends on the point of reference  Technically  both are exactly the same  Both serve the same purpose of transmitting data  to a destination on behalf of a source  The difference lies in  on whose behalf is the proxy server acting   who is the proxy server representing   If the proxy server is forwarding requests to internet server on behalf of the end users  Example  students in a college accessing internet through college proxy server    then the proxy is called  Forward proxy  or simply  Proxy   If the proxy server is responding to incoming requests  on behalf of a server  then the proxy is called  Reverse Proxy   as it is working in the reverse direction  from the point of view of the end user  Some Examples of Reverse proxies   Load balancer in front of web servers acts as a reverse-proxy on behalf of the actual web servers  API gateway Free Website hosting services like  facebook pages   blog page servers  are also reverse proxies  The actual content may be in some web server  but the outside world knows it through specific url advertised by reverse-proxy   Use of forward proxy   Monitor all outbound internet connections from an organization Apply security policies on internet browsing and block malicious content from being downloaded Block access to specific websites  Use of Reverse proxy   Present friendly URL for a website Perform load balancing across multiple web servers Apply security policy and protect actual web servers from attacks

User · Answer

The difference is primarily in deployment  Web forward and reverse proxies all have the same underlying features  They accept requests for HTTP requests in various formats and provide a response  usually by accessing the origin or contact server   Fully featured servers usually have access control  caching  and some link-mapping features   A forward proxy is a proxy that is accessed by configuring the client machine  The client needs protocol support for proxy features  redirection  proxy authentication  etc    The proxy is transparent to the user experience  but not to the application   A reverse proxy is a proxy that is deployed as a web server and behaves like a web server  with the exception that instead of locally composing the content from programs and disk  it forwards the request to an origin server  From the client perspective it is a web server  so the user experience is completely transparent   In fact  a single proxy instance can run as a forward and reverse proxy at the same time for different client populations

User · Answer

A pair of simple definitions would be   Forward Proxy  Acting on behalf of a requestor  or service consumer   Reverse Proxy  Acting on behalf of  service content producer

User · Answer

The best explanation is here with diagrams   While a forward proxy proxies on behalf of clients   or requesting hosts    a reverse proxy proxies on behalf of servers   In effect  whereas a forward proxy hides the identities of clients  a reverse proxy hides the identities of servers

User · Answer

A forward proxy serves users  it helps users access the server   A reverse proxy serves the server  it protects the server from users

User · Answer

Most of the previous answers are good  but in my opinion none comes very close to addressing well enough the  reverse  quality that differentiates the two  To do that  some way of visualizing the  reverse  nature of what is essentially the same thing  a proxy  needs to be given  and it needs to be given in a well abstracted way   A proxy  implicitly  forward proxy   connects multiple local clients to any one remote server   c--     --p--s c--   A reverse proxy connects multiple local servers to any one remote client  notice how the layout reverses    s--     --p--c s--   It is a matter of perspective really and properly understanding the concept requires abstracting away non-essential  to the particular concept  details though they may be very important when it comes to the pragmatics of proxy operation  Such details include the fact that in both scenarios the reality is that multiple clients connect to multiple servers  that clients and servers may not really be local or remote  where the Internet cloud is located or what kind of visibility exists between client and server

User · Answer

A proxy server proxies  and optionally caches  outgoing network requests to various not-necessarily-related public resources across the Internet  A reverse proxy captures  and optionally caches  incoming requests from the Internet and distributes them to various internal private resources  usually for high availability purposes

User · Answer

Proxy  It is making the request on behalf of the client  So  the server will return the response to the proxy  and the proxy will forward the response to the client  In fact  the server will never  learn  who the client was  the client s IP address   it will only know the proxy  However  the client definitely knows the server  since it essentially formats the HTTP request destined for the server  but it just hands it to the proxy     Reverse Proxy  It is receiving the request on behalf of the server  It forwards the request to the server  receives the response and then returns the response to the client  In this case  the client will never  learn  who was the actual server  the server s IP address   with some exceptions   it will only know the proxy  The server will or won t know the actual client  depending on the configurations of the reverse proxy

User · Answer

The previous answers were accurate  but perhaps too terse  I will try to add some examples   First of all  the word  proxy  describes someone or something acting on behalf of someone else   In the computer realm  we are talking about one server acting on the behalf of another computer   For the purposes of accessibility  I will limit my discussion to web proxies - however  the idea of a proxy is not limited to websites   FORWARD proxy  Most discussion of web proxies refers to the type of proxy known as a  forward proxy    The proxy event  in this case  is that the  forward proxy  retrieves data from another web site on behalf of the original requestee   A tale of 3 computers  part I   For an example  I will list three computers connected to the internet    X   your computer  or  client  computer on the internet Y   the proxy web site  proxy example org Z   the web site you want to visit  www example net   Normally  one would connect directly from X -- gt  Z   However  in some scenarios  it is better for Y -- gt  Z on behalf of X  which chains as follows  X -- gt  Y -- gt  Z   Reasons why X would want to use a forward proxy server   Here is a  very  partial list of uses of a forward proxy server    1  X is unable to access Z directly because   a  Someone with administrative authority over X s internet connection has decided to block all access to site Z    Examples    The Storm Worm virus is spreading by tricking people into visiting familypostcards2008 com  so the system administrator has blocked access to the site to prevent users from inadvertently infecting themselves  Employees at a large company have been wasting too much time on facebook com  so management wants access blocked during business hours  A local elementary school disallows internet access to the playboy com website  A government is unable to control the publishing of news  so it controls access to news instead  by blocking sites such as wikipedia org  See TOR or FreeNet    b  The administrator of Z has blocked X    Examples    The administrator of Z has noticed hacking attempts coming from X  so the administrator has decided to block X s IP address  and or netrange   Z is a forum website   X is spamming the forum  Z blocks X       REVERSE proxy  A tale of 3 computers  part II   For this example  I will list three computers connected to the internet    X   your computer  or  client  computer on the internet Y   the reverse proxy web site  proxy example com Z   the web site you want to visit  www example net   Normally  one would connect directly from X -- gt  Z   However  in some scenarios  it is better for the administrator of Z to restrict or disallow direct access and force visitors to go through Y first  So  as before  we have data being retrieved by Y -- gt  Z on behalf of X  which chains as follows  X -- gt  Y -- gt  Z   What is different this time compared to a  forward proxy   is that this time the user X does not know he is accessing Z  because the user X only sees he is communicating with Y  The server Z is invisible to clients and only the reverse proxy Y is visible externally  A reverse proxy requires no  proxy  configuration on the client side   The client X thinks he is only communicating with Y  X -- gt  Y   but the reality is that Y forwarding all communication  X -- gt  Y -- gt  Z again    Reasons why Z would want to set up a reverse proxy server    1  Z wants to force all traffic to its web site to pass through Y first    a  Z has a large web site that millions of people want to see  but a single web server cannot handle all the traffic  So Z sets up many servers and puts a reverse proxy on the internet that will send users to the server closest to them when they try to visit Z  This is part of how the Content Distribution Network  CDN  concept works    Examples    Apple Trailers uses Akamai Jquery com hosts its JavaScript files using CloudFront CDN  sample   etc     2  The administrator of Z is worried about retaliation for content hosted on the server and does not want to expose the main server directly to the public    a  Owners of Spam brands such as  Canadian Pharmacy  appear to have thousands of servers  while in reality having most websites hosted on far fewer servers  Additionally  abuse complaints about the spam will only shut down the public servers  not the main server     In the above scenarios  Z has the ability to choose Y   Links to topics from the post   Content Delivery Network   Lists of CDNs   http   www mytestbox com miscellaneous content-delivery-networks-cdn-list  http   blog streamingmedia com the business of online vi 2008 01 updated-list-of html    Forward proxy software  server side    PHP-Proxy cgi-proxy phproxy   discontinued  glype Internet censorship wiki  List of Web Proxies squid   apparently  can also work as a reverse proxy    Reverse proxy software for HTTP  server side    Apache mod proxy  can also work as a forward proxy for HTTP  nginx   used on hulu com  spam sites  etc   HAProxy Caddy Webserver lighthttpd perlbal  written for livejournal  portfusion pound varnish cache  written by a FreeBSD kernel guru  repose   Reverse proxy software for TCP  server side    balance delegate pen portfusion pure load balancer  web site defunct  python director   See also    Wikipedia - Content Delivery Network Wikipedia - Category Reverse proxy Wikipedia - Load Balancing Wikipedia - Scalability

User · Answer

My understanding from an Apache perspective is that proxy means that if site x proxies for site y  then requests for x return y   The reverse proxy means that the response from y is adjusted so that all references to y become x   So that the user cannot tell that a proxy is involved

User · Answer

Forward Proxy vs  Reverse Proxy  2012  explains the difference between forward and reverse proxies very clearly   qyb2zm302 s answer nicely details applications of proxies  but it slips up on the fundamental concept between forward and reverse proxies  For the reverse proxy  X  rarr  Y  rarr  Z  X knows about Y and not Z  rather than vice versa   A proxy is simply a middleman for communication  requests   responses   Client  lt -  Proxy  lt -  Server   Client proxy    client  lt -  proxy    lt -  server   The proxy acts on behalf of the client  The client knows about all three machines involved in the chain  The server doesn t    Server proxy  client  lt -    proxy  lt -  server     The proxy acts on behalf of the server  The client only knows about the proxy  The server knows the whole chain   It seems to me that forward and reverse are simply confusing  perspective-dependent names for client and server proxy  I suggest abandoning the former for the latter  for explicit communication   Of course  to further complicate the matter  not every machine is exclusively a client or a server  If there is an ambiguity in context  it s best to explicitly specify where the proxy lies  and the communications that it tunnels

User · Answer

Proxy  Forward Proxy    When computers on your LAN connect to a proxy server that accesses the Internet  Benefits include only the server being exposed to the Internet  People on the outside are unable to access the computers directly  Forward proxies can improve Internet access for users by caching downloads  They can also be used to restrict access to certain sites  Also  only the proxy server would need a public address  not the clients connecting to it   Reverse Proxy   A reverse proxy is the opposite of a forward proxy  Instead it acts as a proxy on behalf of the servers being connected to  Instead of accessing a remote server directly  a user would go through the reverse proxy and get directed to the appropriate  server from there  Only the reverse proxy would need an SSL certificate  only one public IP address would be needed  and it can handle load balancing of incoming requests to enhance the overall user experience      Image Source  Creating a Forward Proxy Using Application Request Routing

User · Answer

The difference is primarily in deployment  Web forward and reverse proxies all have the same underlying features  They accept requests for HTTP requests in various formats and provide a response  usually by accessing the origin or contact server   Fully featured servers usually have access control  caching  and some link-mapping features   A forward proxy is a proxy that is accessed by configuring the client machine  The client needs protocol support for proxy features  redirection  proxy authentication  etc    The proxy is transparent to the user experience  but not to the application   A reverse proxy is a proxy that is deployed as a web server and behaves like a web server  with the exception that instead of locally composing the content from programs and disk  it forwards the request to an origin server  From the client perspective it is a web server  so the user experience is completely transparent   In fact  a single proxy instance can run as a forward and reverse proxy at the same time for different client populations

User · Answer

A proxy server proxies  and optionally caches  outgoing network requests to various not-necessarily-related public resources across the Internet  A reverse proxy captures  and optionally caches  incoming requests from the Internet and distributes them to various internal private resources  usually for high availability purposes

User · Answer

Let s consider the purpose of the service  In forward proxy  Proxy helps user to access server  In reverse proxy  Proxy helps server to be accessed by user  In the latter case  the one who is helped by the proxy is no longer a user  but a server  that s the reason why we call it a reverse proxy

User · Answer

I found the diagram below to be very helpful  It just shows the architecture of a forward vs  reverse proxy setup from client to server over the Internet  This image will help you to understand qyb2zm302 s answer and other answers better     You can also watch this video from F5 s DevCentral by Peter Silva   Picture Source  Quora  However  as per Martijn Pieters  this image could be from Pulse Secure Community or Julien Pauli s site  in French  at developpez com   It reminded me of the classic proverb      A picture is worth 1000 words

User · Answer

The difference is primarily in deployment  Web forward and reverse proxies all have the same underlying features  They accept requests for HTTP requests in various formats and provide a response  usually by accessing the origin or contact server   Fully featured servers usually have access control  caching  and some link-mapping features   A forward proxy is a proxy that is accessed by configuring the client machine  The client needs protocol support for proxy features  redirection  proxy authentication  etc    The proxy is transparent to the user experience  but not to the application   A reverse proxy is a proxy that is deployed as a web server and behaves like a web server  with the exception that instead of locally composing the content from programs and disk  it forwards the request to an origin server  From the client perspective it is a web server  so the user experience is completely transparent   In fact  a single proxy instance can run as a forward and reverse proxy at the same time for different client populations

User · Answer

Here s an example of a reverse proxy  as a load balancer    A client surfs to website com and the server it hits has a reverse proxy running on it  The reverse proxy happens to be Pound  Pound takes the request and sends it to one of the three application servers sitting behind it  In this example  Pound is a load balancer  That is  it is balancing the load between three application servers   The application servers serve up the website content back to the client

User · Answer

Difference between Proxy server  also called forward proxy  and Reverse Proxy Server depends on the point of reference  Technically  both are exactly the same  Both serve the same purpose of transmitting data  to a destination on behalf of a source  The difference lies in  on whose behalf is the proxy server acting   who is the proxy server representing   If the proxy server is forwarding requests to internet server on behalf of the end users  Example  students in a college accessing internet through college proxy server    then the proxy is called  Forward proxy  or simply  Proxy   If the proxy server is responding to incoming requests  on behalf of a server  then the proxy is called  Reverse Proxy   as it is working in the reverse direction  from the point of view of the end user  Some Examples of Reverse proxies   Load balancer in front of web servers acts as a reverse-proxy on behalf of the actual web servers  API gateway Free Website hosting services like  facebook pages   blog page servers  are also reverse proxies  The actual content may be in some web server  but the outside world knows it through specific url advertised by reverse-proxy   Use of forward proxy   Monitor all outbound internet connections from an organization Apply security policies on internet browsing and block malicious content from being downloaded Block access to specific websites  Use of Reverse proxy   Present friendly URL for a website Perform load balancing across multiple web servers Apply security policy and protect actual web servers from attacks

User · Answer

Here s an example of a reverse proxy  as a load balancer    A client surfs to website com and the server it hits has a reverse proxy running on it  The reverse proxy happens to be Pound  Pound takes the request and sends it to one of the three application servers sitting behind it  In this example  Pound is a load balancer  That is  it is balancing the load between three application servers   The application servers serve up the website content back to the client

User · Answer

A proxy server proxies  and optionally caches  outgoing network requests to various not-necessarily-related public resources across the Internet  A reverse proxy captures  and optionally caches  incoming requests from the Internet and distributes them to various internal private resources  usually for high availability purposes

User · Answer

The previous answers were accurate  but perhaps too terse  I will try to add some examples   First of all  the word  proxy  describes someone or something acting on behalf of someone else   In the computer realm  we are talking about one server acting on the behalf of another computer   For the purposes of accessibility  I will limit my discussion to web proxies - however  the idea of a proxy is not limited to websites   FORWARD proxy  Most discussion of web proxies refers to the type of proxy known as a  forward proxy    The proxy event  in this case  is that the  forward proxy  retrieves data from another web site on behalf of the original requestee   A tale of 3 computers  part I   For an example  I will list three computers connected to the internet    X   your computer  or  client  computer on the internet Y   the proxy web site  proxy example org Z   the web site you want to visit  www example net   Normally  one would connect directly from X -- gt  Z   However  in some scenarios  it is better for Y -- gt  Z on behalf of X  which chains as follows  X -- gt  Y -- gt  Z   Reasons why X would want to use a forward proxy server   Here is a  very  partial list of uses of a forward proxy server    1  X is unable to access Z directly because   a  Someone with administrative authority over X s internet connection has decided to block all access to site Z    Examples    The Storm Worm virus is spreading by tricking people into visiting familypostcards2008 com  so the system administrator has blocked access to the site to prevent users from inadvertently infecting themselves  Employees at a large company have been wasting too much time on facebook com  so management wants access blocked during business hours  A local elementary school disallows internet access to the playboy com website  A government is unable to control the publishing of news  so it controls access to news instead  by blocking sites such as wikipedia org  See TOR or FreeNet    b  The administrator of Z has blocked X    Examples    The administrator of Z has noticed hacking attempts coming from X  so the administrator has decided to block X s IP address  and or netrange   Z is a forum website   X is spamming the forum  Z blocks X       REVERSE proxy  A tale of 3 computers  part II   For this example  I will list three computers connected to the internet    X   your computer  or  client  computer on the internet Y   the reverse proxy web site  proxy example com Z   the web site you want to visit  www example net   Normally  one would connect directly from X -- gt  Z   However  in some scenarios  it is better for the administrator of Z to restrict or disallow direct access and force visitors to go through Y first  So  as before  we have data being retrieved by Y -- gt  Z on behalf of X  which chains as follows  X -- gt  Y -- gt  Z   What is different this time compared to a  forward proxy   is that this time the user X does not know he is accessing Z  because the user X only sees he is communicating with Y  The server Z is invisible to clients and only the reverse proxy Y is visible externally  A reverse proxy requires no  proxy  configuration on the client side   The client X thinks he is only communicating with Y  X -- gt  Y   but the reality is that Y forwarding all communication  X -- gt  Y -- gt  Z again    Reasons why Z would want to set up a reverse proxy server    1  Z wants to force all traffic to its web site to pass through Y first    a  Z has a large web site that millions of people want to see  but a single web server cannot handle all the traffic  So Z sets up many servers and puts a reverse proxy on the internet that will send users to the server closest to them when they try to visit Z  This is part of how the Content Distribution Network  CDN  concept works    Examples    Apple Trailers uses Akamai Jquery com hosts its JavaScript files using CloudFront CDN  sample   etc     2  The administrator of Z is worried about retaliation for content hosted on the server and does not want to expose the main server directly to the public    a  Owners of Spam brands such as  Canadian Pharmacy  appear to have thousands of servers  while in reality having most websites hosted on far fewer servers  Additionally  abuse complaints about the spam will only shut down the public servers  not the main server     In the above scenarios  Z has the ability to choose Y   Links to topics from the post   Content Delivery Network   Lists of CDNs   http   www mytestbox com miscellaneous content-delivery-networks-cdn-list  http   blog streamingmedia com the business of online vi 2008 01 updated-list-of html    Forward proxy software  server side    PHP-Proxy cgi-proxy phproxy   discontinued  glype Internet censorship wiki  List of Web Proxies squid   apparently  can also work as a reverse proxy    Reverse proxy software for HTTP  server side    Apache mod proxy  can also work as a forward proxy for HTTP  nginx   used on hulu com  spam sites  etc   HAProxy Caddy Webserver lighthttpd perlbal  written for livejournal  portfusion pound varnish cache  written by a FreeBSD kernel guru  repose   Reverse proxy software for TCP  server side    balance delegate pen portfusion pure load balancer  web site defunct  python director   See also    Wikipedia - Content Delivery Network Wikipedia - Category Reverse proxy Wikipedia - Load Balancing Wikipedia - Scalability

User · Answer

The previous answers were accurate  but perhaps too terse  I will try to add some examples   First of all  the word  proxy  describes someone or something acting on behalf of someone else   In the computer realm  we are talking about one server acting on the behalf of another computer   For the purposes of accessibility  I will limit my discussion to web proxies - however  the idea of a proxy is not limited to websites   FORWARD proxy  Most discussion of web proxies refers to the type of proxy known as a  forward proxy    The proxy event  in this case  is that the  forward proxy  retrieves data from another web site on behalf of the original requestee   A tale of 3 computers  part I   For an example  I will list three computers connected to the internet    X   your computer  or  client  computer on the internet Y   the proxy web site  proxy example org Z   the web site you want to visit  www example net   Normally  one would connect directly from X -- gt  Z   However  in some scenarios  it is better for Y -- gt  Z on behalf of X  which chains as follows  X -- gt  Y -- gt  Z   Reasons why X would want to use a forward proxy server   Here is a  very  partial list of uses of a forward proxy server    1  X is unable to access Z directly because   a  Someone with administrative authority over X s internet connection has decided to block all access to site Z    Examples    The Storm Worm virus is spreading by tricking people into visiting familypostcards2008 com  so the system administrator has blocked access to the site to prevent users from inadvertently infecting themselves  Employees at a large company have been wasting too much time on facebook com  so management wants access blocked during business hours  A local elementary school disallows internet access to the playboy com website  A government is unable to control the publishing of news  so it controls access to news instead  by blocking sites such as wikipedia org  See TOR or FreeNet    b  The administrator of Z has blocked X    Examples    The administrator of Z has noticed hacking attempts coming from X  so the administrator has decided to block X s IP address  and or netrange   Z is a forum website   X is spamming the forum  Z blocks X       REVERSE proxy  A tale of 3 computers  part II   For this example  I will list three computers connected to the internet    X   your computer  or  client  computer on the internet Y   the reverse proxy web site  proxy example com Z   the web site you want to visit  www example net   Normally  one would connect directly from X -- gt  Z   However  in some scenarios  it is better for the administrator of Z to restrict or disallow direct access and force visitors to go through Y first  So  as before  we have data being retrieved by Y -- gt  Z on behalf of X  which chains as follows  X -- gt  Y -- gt  Z   What is different this time compared to a  forward proxy   is that this time the user X does not know he is accessing Z  because the user X only sees he is communicating with Y  The server Z is invisible to clients and only the reverse proxy Y is visible externally  A reverse proxy requires no  proxy  configuration on the client side   The client X thinks he is only communicating with Y  X -- gt  Y   but the reality is that Y forwarding all communication  X -- gt  Y -- gt  Z again    Reasons why Z would want to set up a reverse proxy server    1  Z wants to force all traffic to its web site to pass through Y first    a  Z has a large web site that millions of people want to see  but a single web server cannot handle all the traffic  So Z sets up many servers and puts a reverse proxy on the internet that will send users to the server closest to them when they try to visit Z  This is part of how the Content Distribution Network  CDN  concept works    Examples    Apple Trailers uses Akamai Jquery com hosts its JavaScript files using CloudFront CDN  sample   etc     2  The administrator of Z is worried about retaliation for content hosted on the server and does not want to expose the main server directly to the public    a  Owners of Spam brands such as  Canadian Pharmacy  appear to have thousands of servers  while in reality having most websites hosted on far fewer servers  Additionally  abuse complaints about the spam will only shut down the public servers  not the main server     In the above scenarios  Z has the ability to choose Y   Links to topics from the post   Content Delivery Network   Lists of CDNs   http   www mytestbox com miscellaneous content-delivery-networks-cdn-list  http   blog streamingmedia com the business of online vi 2008 01 updated-list-of html    Forward proxy software  server side    PHP-Proxy cgi-proxy phproxy   discontinued  glype Internet censorship wiki  List of Web Proxies squid   apparently  can also work as a reverse proxy    Reverse proxy software for HTTP  server side    Apache mod proxy  can also work as a forward proxy for HTTP  nginx   used on hulu com  spam sites  etc   HAProxy Caddy Webserver lighthttpd perlbal  written for livejournal  portfusion pound varnish cache  written by a FreeBSD kernel guru  repose   Reverse proxy software for TCP  server side    balance delegate pen portfusion pure load balancer  web site defunct  python director   See also    Wikipedia - Content Delivery Network Wikipedia - Category Reverse proxy Wikipedia - Load Balancing Wikipedia - Scalability

User · Answer

A forward proxy serves users  it helps users access the server   A reverse proxy serves the server  it protects the server from users

User · Answer

My understanding from an Apache perspective is that proxy means that if site x proxies for site y  then requests for x return y   The reverse proxy means that the response from y is adjusted so that all references to y become x   So that the user cannot tell that a proxy is involved

User · Answer

I found the diagram below to be very helpful  It just shows the architecture of a forward vs  reverse proxy setup from client to server over the Internet  This image will help you to understand qyb2zm302 s answer and other answers better     You can also watch this video from F5 s DevCentral by Peter Silva   Picture Source  Quora  However  as per Martijn Pieters  this image could be from Pulse Secure Community or Julien Pauli s site  in French  at developpez com   It reminded me of the classic proverb      A picture is worth 1000 words

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The best explanation is here with diagrams   While a forward proxy proxies on behalf of clients   or requesting hosts    a reverse proxy proxies on behalf of servers   In effect  whereas a forward proxy hides the identities of clients  a reverse proxy hides the identities of servers

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Forward proxies grant the client anonymity  i e  think Tor    Reverse proxies grant back end servers anonymity  i e  think servers behind a DMZ

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Cloudflare has a great article with images explaining this in details       Check here    What Is A Reverse Proxy    Proxy Servers Explained

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Most of the previous answers are good  but in my opinion none comes very close to addressing well enough the  reverse  quality that differentiates the two  To do that  some way of visualizing the  reverse  nature of what is essentially the same thing  a proxy  needs to be given  and it needs to be given in a well abstracted way   A proxy  implicitly  forward proxy   connects multiple local clients to any one remote server   c--     --p--s c--   A reverse proxy connects multiple local servers to any one remote client  notice how the layout reverses    s--     --p--c s--   It is a matter of perspective really and properly understanding the concept requires abstracting away non-essential  to the particular concept  details though they may be very important when it comes to the pragmatics of proxy operation  Such details include the fact that in both scenarios the reality is that multiple clients connect to multiple servers  that clients and servers may not really be local or remote  where the Internet cloud is located or what kind of visibility exists between client and server

User · Answer

The previous answers were accurate  but perhaps too terse  I will try to add some examples   First of all  the word  proxy  describes someone or something acting on behalf of someone else   In the computer realm  we are talking about one server acting on the behalf of another computer   For the purposes of accessibility  I will limit my discussion to web proxies - however  the idea of a proxy is not limited to websites   FORWARD proxy  Most discussion of web proxies refers to the type of proxy known as a  forward proxy    The proxy event  in this case  is that the  forward proxy  retrieves data from another web site on behalf of the original requestee   A tale of 3 computers  part I   For an example  I will list three computers connected to the internet    X   your computer  or  client  computer on the internet Y   the proxy web site  proxy example org Z   the web site you want to visit  www example net   Normally  one would connect directly from X -- gt  Z   However  in some scenarios  it is better for Y -- gt  Z on behalf of X  which chains as follows  X -- gt  Y -- gt  Z   Reasons why X would want to use a forward proxy server   Here is a  very  partial list of uses of a forward proxy server    1  X is unable to access Z directly because   a  Someone with administrative authority over X s internet connection has decided to block all access to site Z    Examples    The Storm Worm virus is spreading by tricking people into visiting familypostcards2008 com  so the system administrator has blocked access to the site to prevent users from inadvertently infecting themselves  Employees at a large company have been wasting too much time on facebook com  so management wants access blocked during business hours  A local elementary school disallows internet access to the playboy com website  A government is unable to control the publishing of news  so it controls access to news instead  by blocking sites such as wikipedia org  See TOR or FreeNet    b  The administrator of Z has blocked X    Examples    The administrator of Z has noticed hacking attempts coming from X  so the administrator has decided to block X s IP address  and or netrange   Z is a forum website   X is spamming the forum  Z blocks X       REVERSE proxy  A tale of 3 computers  part II   For this example  I will list three computers connected to the internet    X   your computer  or  client  computer on the internet Y   the reverse proxy web site  proxy example com Z   the web site you want to visit  www example net   Normally  one would connect directly from X -- gt  Z   However  in some scenarios  it is better for the administrator of Z to restrict or disallow direct access and force visitors to go through Y first  So  as before  we have data being retrieved by Y -- gt  Z on behalf of X  which chains as follows  X -- gt  Y -- gt  Z   What is different this time compared to a  forward proxy   is that this time the user X does not know he is accessing Z  because the user X only sees he is communicating with Y  The server Z is invisible to clients and only the reverse proxy Y is visible externally  A reverse proxy requires no  proxy  configuration on the client side   The client X thinks he is only communicating with Y  X -- gt  Y   but the reality is that Y forwarding all communication  X -- gt  Y -- gt  Z again    Reasons why Z would want to set up a reverse proxy server    1  Z wants to force all traffic to its web site to pass through Y first    a  Z has a large web site that millions of people want to see  but a single web server cannot handle all the traffic  So Z sets up many servers and puts a reverse proxy on the internet that will send users to the server closest to them when they try to visit Z  This is part of how the Content Distribution Network  CDN  concept works    Examples    Apple Trailers uses Akamai Jquery com hosts its JavaScript files using CloudFront CDN  sample   etc     2  The administrator of Z is worried about retaliation for content hosted on the server and does not want to expose the main server directly to the public    a  Owners of Spam brands such as  Canadian Pharmacy  appear to have thousands of servers  while in reality having most websites hosted on far fewer servers  Additionally  abuse complaints about the spam will only shut down the public servers  not the main server     In the above scenarios  Z has the ability to choose Y   Links to topics from the post   Content Delivery Network   Lists of CDNs   http   www mytestbox com miscellaneous content-delivery-networks-cdn-list  http   blog streamingmedia com the business of online vi 2008 01 updated-list-of html    Forward proxy software  server side    PHP-Proxy cgi-proxy phproxy   discontinued  glype Internet censorship wiki  List of Web Proxies squid   apparently  can also work as a reverse proxy    Reverse proxy software for HTTP  server side    Apache mod proxy  can also work as a forward proxy for HTTP  nginx   used on hulu com  spam sites  etc   HAProxy Caddy Webserver lighthttpd perlbal  written for livejournal  portfusion pound varnish cache  written by a FreeBSD kernel guru  repose   Reverse proxy software for TCP  server side    balance delegate pen portfusion pure load balancer  web site defunct  python director   See also    Wikipedia - Content Delivery Network Wikipedia - Category Reverse proxy Wikipedia - Load Balancing Wikipedia - Scalability

User · Answer

As per my understanding    To start with  as everyone knows  proxy means  quot the authority to represent someone else quot   Now there are two things  forward and reverse proxy  Forward proxy Suppose you want to access  quot Google quot  and  quot Google quot  in turn will have n number of servers to respond to that particular request  Now in this case  while you are requesting for something from Google and you don   t want Google to see your IP address  then you will use a forward proxy  as explained below  A   B   C Now here you are A  sending a request through B  So C will think that the request is coming from B  not A  In this way you can prevent your clients IP address not to be exposed to outer world  Reverse proxy Now in this case  to make you understand  we will take the same case of forward proxy  Here you have requested for something to Google  which in turn going to send the one request to the app server or another proxy server to get the response  So these things will happen as explained below  A    B    C C    D C    D A   B   C From the above diagram you can see that a request has been sent to C from B  not from A  Then from C there will be one request send to D  Similarly the response will go to C from D and then to B and A  The above diagram says it s only the context which matters although both the proxies are acting the same way  but the client-side proxy is hiding the client information whereas the server-side proxy will hide server-side information

User · Answer

Proxy  It is making the request on behalf of the client  So  the server will return the response to the proxy  and the proxy will forward the response to the client  In fact  the server will never  learn  who the client was  the client s IP address   it will only know the proxy  However  the client definitely knows the server  since it essentially formats the HTTP request destined for the server  but it just hands it to the proxy     Reverse Proxy  It is receiving the request on behalf of the server  It forwards the request to the server  receives the response and then returns the response to the client  In this case  the client will never  learn  who was the actual server  the server s IP address   with some exceptions   it will only know the proxy  The server will or won t know the actual client  depending on the configurations of the reverse proxy

User · Answer

Looking from the perspective of the user  when sending a request to a proxy or reverse proxy server    proxy - requires two arguments  1  what to get and 2  which proxy server to use an intermediate reverse proxy - requires one argument  1  what to get   A reverse proxy fetches contents from another server unbeknownst to the user and returns the result as if it originated from the reverse proxy server

User · Answer

Forward Proxy vs  Reverse Proxy  2012  explains the difference between forward and reverse proxies very clearly   qyb2zm302 s answer nicely details applications of proxies  but it slips up on the fundamental concept between forward and reverse proxies  For the reverse proxy  X  rarr  Y  rarr  Z  X knows about Y and not Z  rather than vice versa   A proxy is simply a middleman for communication  requests   responses   Client  lt -  Proxy  lt -  Server   Client proxy    client  lt -  proxy    lt -  server   The proxy acts on behalf of the client  The client knows about all three machines involved in the chain  The server doesn t    Server proxy  client  lt -    proxy  lt -  server     The proxy acts on behalf of the server  The client only knows about the proxy  The server knows the whole chain   It seems to me that forward and reverse are simply confusing  perspective-dependent names for client and server proxy  I suggest abandoning the former for the latter  for explicit communication   Of course  to further complicate the matter  not every machine is exclusively a client or a server  If there is an ambiguity in context  it s best to explicitly specify where the proxy lies  and the communications that it tunnels

[proxy] What's the difference between a proxy server and a reverse proxy server?

Forward proxy

Reverse proxy

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