How can I check if an ip is in a network in Python

Question

Given an ip address  say 192 168 0 1   how do I check if it s in a network  say 192 168 0 0 24  in Python   Are there general tools in Python for ip address manipulation  Stuff like host lookups  ip adddress to int  network address with netmask to int and so on  Hopefully in the standard Python library for 2 5

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I like to use netaddr for that   from netaddr import CIDR  IP  if IP  192 168 0 1   in CIDR  192 168 0 0 24        print  Yay     As arno v pointed out in the comments  new version of netaddr does it like this   from netaddr import IPNetwork  IPAddress if IPAddress  192 168 0 1   in IPNetwork  192 168 0 0 24        print  Yay

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From various sources above  and from my own research  this is how I got subnet and address calculation working   These pieces are enough to solve the question and other related questions   class iptools       staticmethod     def dottedQuadToNum ip            convert decimal dotted quad string to long integer          return struct unpack   gt L   socket inet aton ip   0        staticmethod     def numToDottedQuad n            convert long int to dotted quad string          return socket inet ntoa struct pack   gt L   n         staticmethod     def makeNetmask mask           bits   0         for i in xrange 32-int mask   32               bits     1  lt  lt  i          return bits       staticmethod     def ipToNetAndHost ip  maskbits            returns tuple  network  host  dotted-quad addresses given            IP and mask size             by Greg Jorgensen          n   iptools dottedQuadToNum ip          m   iptools makeMask maskbits          net   n  amp  m         host   n - mask         return iptools numToDottedQuad net   iptools numToDottedQuad host

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previous solution have a bug in ip  amp  net    net  Correct ip lookup is ip  amp  netmask   net  bugfixed code   import socket import struct  def makeMask n        return a mask of n bits as a long integer      return  2L lt  lt n-1  - 1  def dottedQuadToNum ip        convert decimal dotted quad string to long integer      return struct unpack  L  socket inet aton ip   0   def addressInNetwork ip net netmask       Is an address in a network     print  IP   str ip      NET   str net      MASK   str netmask    AND   str ip  amp  netmask     return ip  amp  netmask    net  def humannetcheck ip net           address dottedQuadToNum ip          netaddr dottedQuadToNum net split      0           netmask makeMask long net split      1            return addressInNetwork address netaddr netmask    print humannetcheck  192 168 0 1   192 168 0 0 24    print humannetcheck  192 169 0 1   192 168 0 0 24

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Wherever possible I d recommend the built in ipaddress module  It s only available in Python 3 though  but it is super easy to use  and supports IPv6  And why aren t you using Python 3 yet anyway  right   The accepted answer doesn t work     which is making me angry  Mask is backwards and doesn t work with any bits that are not a simple 8 bit block  eg  24   I adapted the answer  and it works nicely      import socket struct          def addressInNetwork ip  net n bits           ipaddr   struct unpack   L   socket inet aton ip   0        net  bits   net n bits split            netaddr   struct unpack   L   socket inet aton net   0        netmask    0xFFFFFFFF  gt  gt  int bits     0xFFFFFFFF       return ipaddr  amp  netmask    netaddr  here is a function that returns a dotted binary string to help visualize the masking   kind of like ipcalc output      def bb i        def s      032b   format i       def return s 0 8   quot   quot  s 8 16   quot   quot  s 16 24   quot   quot  s 24 32   eg

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Not in the Standard library for 2 5  but ipaddr makes this very easy  I believe it is in 3 3 under the name ipaddress    import ipaddr  a   ipaddr IPAddress  192 168 0 1   n   ipaddr IPNetwork  192 168 0 0 24     This will return True n Contains a

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I tried one subset of proposed solutions in these answers   with no success  I finally adapted and fixed the proposed code and wrote my fixed function    I tested it and works at least on little endian architectures--e g x86-- if anyone likes to try on a big endian architecture  please give me feedback   IP2Int code comes from this post  the other method is a fully  for my test cases  working fix of previous proposals in this question    The code   def IP2Int ip       o   map int  ip split           res    16777216   o 0      65536   o 1      256   o 2     o 3      return res   def addressInNetwork ip  net n bits       ipaddr   IP2Int ip      net  bits   net n bits split          netaddr   IP2Int net      bits num   int bits      netmask     1L  lt  lt  bits num  - 1   lt  lt   32 - bits num      return ipaddr  amp  netmask    netaddr  amp  netmask   Hope useful

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For python3  import ipaddress ipaddress IPv4Address  192 168 1 1   in ipaddress IPv4Network  192 168 0 0 24   ipaddress IPv4Address  192 168 1 1   in ipaddress IPv4Network  192 168 0 0 16     Output    False True

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There is an API that s called SubnetTree available in python that do this job very well   This is a simple example     import SubnetTree t   SubnetTree SubnetTree   t insert  10 0 1 3 32   print  10 0 1 3  in t    This is the link

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Here is my code    - - coding  utf-8 - - import socket   class SubnetTest object       def   init   self  network           self network  self netmask   network split              self  network int   int socket inet aton self network  encode  hex    16          self  mask     1L  lt  lt  int self netmask   - 1   lt  lt   32 - int self netmask           self  net prefix   self  network int  amp  self  mask      def match self  ip                             IP      Network    IP                     ip int   int socket inet aton ip  encode  hex    16          return  ip int  amp  self  mask     self  net prefix  st   SubnetTest  100 98 21 0 24   print st match  100 98 23 32

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I m not a fan of using modules when they are not needed   This job only requires simple math  so here is my simple function to do the job   def ipToInt ip       o   map int  ip split           res    16777216   o 0      65536   o 1      256   o 2     o 3      return res  def isIpInSubnet ip  ipNetwork  maskLength       ipInt   ipToInt ip  my test ip  in int form      maskLengthFromRight   32 - maskLength      ipNetworkInt   ipToInt ipNetwork   convert the ip network into integer form     binString     0 b   format ipNetworkInt   convert that into into binary  string format       chopAmount   0  find out how much of that int I need to cut off     for i in range maskLengthFromRight           if i  lt  len binString               chopAmount    int binString len binString -1-i     2  i      minVal   ipNetworkInt-chopAmount     maxVal   minVal 2  maskLengthFromRight -1      return minVal  lt   ipInt and ipInt  lt   maxVal   Then to use it    gt  gt  gt  print isIpInSubnet  66 151 97 0    66 151 97 192  24   True  gt  gt  gt  print isIpInSubnet  66 151 97 193    66 151 97 192  29   True  gt  gt  gt  print isIpInSubnet  66 151 96 0    66 151 97 192  24   False  gt  gt  gt  print isIpInSubnet  66 151 97 0    66 151 97 192  29     That s it  this is much faster than the solutions above with the included modules

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Here is the solution using netaddr package  from netaddr import IPNetwork  IPAddress   def network has ip network  ip        if not isinstance network  IPNetwork           raise Exception  network parameter must be  0  instance  format IPNetwork   name          if not isinstance ip  IPAddress           raise Exception  ip parameter must be  0  instance  format IPAddress   name          return  network cidr ip value  amp  network netmask value      ip value  amp  network netmask value

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This article shows you can do it with socket and struct modules without too much extra effort   I added a little to the article as follows   import socket struct  def makeMask n        return a mask of n bits as a long integer      return  2L lt  lt n-1  - 1  def dottedQuadToNum ip        convert decimal dotted quad string to long integer      return struct unpack  L  socket inet aton ip   0   def networkMask ip bits        Convert a network address to a long integer       return dottedQuadToNum ip   amp  makeMask bits   def addressInNetwork ip net       Is an address in a network     return ip  amp  net    net  address   dottedQuadToNum  192 168 1 1   networka   networkMask  10 0 0 0  24  networkb   networkMask  192 168 0 0  24  print  address networka networkb  print addressInNetwork address networka  print addressInNetwork address networkb    This outputs   False True   If you just want a single function that takes strings it would look like this   import socket struct  def addressInNetwork ip net       Is an address in a network     ipaddr   struct unpack  L  socket inet aton ip   0     netaddr bits   net split         netmask   struct unpack  L  socket inet aton netaddr   0   amp    2L lt  lt int bits -1  - 1     return ipaddr  amp  netmask    netmask

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The choosen answer has a bug   Following is the correct code   def addressInNetwork ip  net n bits      ipaddr   struct unpack   lt L   socket inet aton ip   0     net  bits   net n bits split         netaddr   struct unpack   lt L   socket inet aton net   0     netmask     1L  lt  lt  int bits   - 1     return ipaddr  amp  netmask    netaddr  amp  netmask   Note  ipaddr  amp  netmask    netaddr  amp  netmask instead of ipaddr  amp  netmask    netmask    I also replace   2L lt  lt int bits -1  - 1  with   1L  lt  lt  int bits   - 1   as the latter seems more understandable

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If you do not want to import other modules you could go with   def ip matches network self  network  ip                  08b   format 254   Converts 254 in a string of its binary representation      ip bits  net mask     net ip bits  net mask   compare the ip bit streams       param network  string like  192 168 33 0 24       param ip  string like  192 168 33 1       return  if ip matches network             net ip  net mask   network split          net mask   int net mask      ip bits      join    08b   format int x   for x in ip split           net ip bits      join    08b   format int x   for x in net ip split             example  net mask 24 - gt  compare strings at position 0 to 23     return ip bits  net mask     net ip bits  net mask

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This code is working for me on Linux x86   I haven t really given any thought to endianess issues  but I have tested it against the  ipaddr  module using over 200K IP addresses tested against 8 different network strings  and the results of ipaddr are the same as this code   def addressInNetwork ip  net      import socket struct    ipaddr   int    join     02x    int x  for x in ip split          16     netstr  bits   net split         netaddr   int    join     02x    int x  for x in netstr split          16     mask    0xffffffff  lt  lt   32 - int bits     amp  0xffffffff    return  ipaddr  amp  mask      netaddr  amp  mask    Example    gt  gt  gt  print addressInNetwork  10 9 8 7    10 9 1 0 16   True  gt  gt  gt  print addressInNetwork  10 9 8 7    10 9 1 0 24   False

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Using ipaddress  in the stdlib since 3 3  at PyPi for 2 6 2 7     gt  gt  gt  import ipaddress  gt  gt  gt  ipaddress ip address  192 168 0 1   in ipaddress ip network  192 168 0 0 24   True     If you want to evaluate a lot of IP addresses this way  you ll probably want to calculate the netmask upfront  like  n   ipaddress ip network  192 0 0 0 16   netw   int n network address  mask   int n netmask    Then  for each address  calculate the binary representation with one of  a   int ipaddress ip address  192 0 43 10    a   struct unpack   I   socket inet pton socket AF INET   192 0 43 10    0  a   struct unpack   I   socket inet aton  192 0 43 10    0     IPv4 only   Finally  you can simply check   in network    a  amp  mask     netw

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import socket struct def addressInNetwork ip net        Is an address in a network      ipaddr   struct unpack   L  socket inet aton ip   0      netaddr bits   net split          netaddr   struct unpack   L  socket inet aton netaddr   0      netmask     1 lt  lt  32-int bits    - 1  0xffffffff     return ipaddr  amp  netmask    netaddr  amp  netmask print addressInNetwork  10 10 10 110   10 10 10 128 25   print addressInNetwork  10 10 10 110   10 10 10 0 25   print addressInNetwork  10 10 10 110   10 20 10 128 25       python check-subnet py False True False

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from netaddr import all matching cidrs   gt  gt  gt  from netaddr import all matching cidrs  gt  gt  gt  all matching cidrs  212 11 70 34     192 168 0 0 24   212 11 64 0 19      IPNetwork  212 11 64 0 19      Here is the usage for this method    gt  gt  gt  help all matching cidrs   Help on function all matching cidrs in module netaddr ip   all matching cidrs ip  cidrs      Matches an IP address or subnet against a given sequence of IP addresses and subnets        param ip  a single IP address or subnet        param cidrs  a sequence of IP addresses and or subnets        return  all matching IPAddress and or IPNetwork objects from the provided     sequence  an empty list if there was no match    Basically you provide an ip address as the first argument and a list of cidrs as the second argument   A list of hits are returned

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Relying on the  struct  module can cause problems with endian-ness and type sizes  and just isn t needed  Nor is socket inet aton    Python works very well with dotted-quad IP addresses   def ip to u32 ip     return int    join   02x    int d  for d in ip split        16    I need to do IP matching on each socket accept   call  against a whole set of allowable source networks  so I precompute masks and networks  as integers   SNS SOURCES         US-EAST-1    207 171 167 101      207 171 167 25      207 171 167 26      207 171 172 6      54 239 98 0 24      54 240 217 16 29      54 240 217 8 29      54 240 217 64 28      54 240 217 80 29      72 21 196 64 29      72 21 198 64 29      72 21 198 72      72 21 217 0 24        def build masks      masks         for cidr in SNS SOURCES      if     in cidr        netstr  bits   cidr split            mask    0xffffffff  lt  lt   32 - int bits     amp  0xffffffff       net   ip to u32 netstr   amp  mask     else        mask   0xffffffff       net   ip to u32 cidr      masks append  mask  net     return masks   Then I can quickly see if a given IP is within one of those networks   ip   ip to u32 ipstr  for mask  net in cached masks    if ip  amp  mask    net        matched      break else    raise BadClientIP ipstr    No module imports needed  and the code is very fast at matching

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Using Python3 ipaddress   import ipaddress  address   ipaddress ip address  192 168 0 1   network   ipaddress ip network  192 168 0 0 16    print network supernet of ipaddress ip network f  address   address max prefixlen          Explanation  You can think of an IP Address as a Network with the largest possible netmask   32 for IPv4   128 for IPv6   Checking whether 192 168 0 1 is in 192 168 0 0 16 is essentially the same as checking whether 192 168 0 1 32 is a subnet of 192 168 0 0 16

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Thank you for your script  I have work quite a long on it to make everything working    So I m sharing it here   Using netaddr Class is 10 times slower than using binary conversion  so if you d like to use it on a big list of IP  you should consider not using netaddr class makeMask function is not working  Only working for  8  16  24 Ex      bits    21    socket inet ntoa struct pack   L   2L  lt  lt  int bits -1  - 1      255 255 31 0  whereas it should be 255 255 248 0   So I have used another function calcDottedNetmask mask  from  http   code activestate com recipes 576483-convert-subnetmask-from-cidr-notation-to-dotdecima   Ex        usr bin python     calcDottedNetmask 21       255 255 248 0     Another problem is the process of matching if an IP belongs to a network  Basic Operation should be to compare  ipaddr  amp  netmask  and  network  amp  netmask  Ex  for the time being  the function is wrong       usr bin python     addressInNetwork  188 104 8 64   172 16 0 0 12      True which is completely WRONG     So my new addressInNetwork function looks-like       usr bin python import socket struct def addressInNetwork ip net          This function allows you to check if on IP belogs to a Network        ipaddr   struct unpack   L  socket inet aton ip   0      netaddr bits   net split          netmask   struct unpack   L  socket inet aton calcDottedNetmask bits    0      network   struct unpack   L  socket inet aton netaddr   0    netmask     return  ipaddr   netmask      network   netmask   def calcDottedNetmask mask       bits   0     for i in xrange 32-int mask  32           bits     1   24   bits   0xff0000     16   bits   0xff00     8    bits   0xff       And now  answer is right        usr bin python     addressInNetwork  188 104 8 64   172 16 0 0 12   False   I hope that it will help other people  saving time for them

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Here is a class I wrote for longest prefix matching      usr bin env python  class Node  def   init   self       self left child   None     self right child   None     self data    -   def setData self  data   self data   data def setLeft self  pointer   self left child   pointer def setRight self  pointer   self right child   pointer def getData self   return self data def getLeft self   return self left child def getRight self   return self right child  def   str   self           return  LC   s RC   s data   s     self left child  self right child  self data    class LPMTrie         def   init   self       self nodes    Node        self curr node ind   0  def addPrefix self  prefix       self curr node ind   0     prefix bits      join  bin int x  256  3   for x in prefix split      0  split            prefix length   int prefix split      1       for i in xrange 0  prefix length           if  prefix bits i      1                if  self nodes self curr node ind  getRight                     self curr node ind   self nodes self curr node ind  getRight               else                  tmp   Node                   self nodes self curr node ind  setRight len self nodes                   tmp setData self nodes self curr node ind  getData                     self curr node ind   len self nodes                  self nodes append tmp          else              if  self nodes self curr node ind  getLeft                     self curr node ind   self nodes self curr node ind  getLeft               else                  tmp   Node                   self nodes self curr node ind  setLeft len self nodes                   tmp setData self nodes self curr node ind  getData                     self curr node ind   len self nodes                  self nodes append tmp           if i    prefix length - 1               self nodes self curr node ind  setData prefix   def searchPrefix self  ip       self curr node ind   0     ip bits      join  bin int x  256  3   for x in ip split            for i in xrange 0  32           if  ip bits i      1                if  self nodes self curr node ind  getRight                     self curr node ind   self nodes self curr node ind  getRight               else                  return self nodes self curr node ind  getData           else              if  self nodes self curr node ind  getLeft                     self curr node ind   self nodes self curr node ind  getLeft               else                  return self nodes self curr node ind  getData        return None  def triePrint self       n   1     for i in self nodes          print n              print i         n    1   And here is a test program   n LPMTrie   n addPrefix  10 25 63 0 24   n addPrefix  10 25 63 0 16   n addPrefix  100 25 63 2 8   n addPrefix  100 25 0 3 16   print n searchPrefix  10 25 63 152   print n searchPrefix  100 25 63 200    10 25 63 0 24  100 25 0 3 16

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This works properly without the weird byte by byte handling def addressInNetwork ip net          Is an address in a network          Convert addresses to host order  so shifts actually make sense     ip   struct unpack   L  socket inet aton ip   0      netaddr bits   net split          netaddr   struct unpack   L  socket inet aton netaddr   0        Must shift left an all ones value   32   zero shift   0   32 shift left     netmask    0xffffffff  lt lt  32-int bits      0xffffffff       There s no need to mask the network address  as long as its a proper network address     return  ip   netmask     netaddr

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I tried Dave Webb s solution but hit some problems   Most fundamentally - a match should be checked by ANDing the IP address with the mask  then checking the result matched the Network address exactly  Not ANDing the IP address with the Network address as was done   I also noticed that just ignoring the Endian behaviour assuming that consistency will save you will only work for masks on octet boundaries   24   16   In order to get other masks   23   21  working correctly I added a  greater than  to the struct commands and changed the code for creating the binary mask to start with all  1  and shift left by  32-mask     Finally  I added a simple check that the network address is valid for the mask and just print a warning if it is not   Here s the result   def addressInNetwork ip net        Is an address in a network      ipaddr   struct unpack   gt L  socket inet aton ip   0      netaddr bits   net split          netmask   struct unpack   gt L  socket inet aton netaddr   0      ipaddr masked   ipaddr  amp   4294967295 lt  lt  32-int bits        Logical AND of IP address and mask will equal the network address if it matches     if netmask    netmask  amp   4294967295 lt  lt  32-int bits         Validate network address is valid for mask             return ipaddr masked    netmask     else              print     WARNING    Network  netaddr  not valid with mask    bits             return ipaddr masked    netmask

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I don t know of anything in the standard library  but PySubnetTree is a Python library that will do subnet matching

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Marc s code is nearly correct  A complete version of the code is -  def addressInNetwork3 ip net          This function allows you to check if on IP belogs to a Network        ipaddr   struct unpack   L  socket inet aton ip   0      netaddr bits   net split          netmask   struct unpack   L  socket inet aton calcDottedNetmask int bits     0      network   struct unpack   L  socket inet aton netaddr   0   amp  netmask     return  ipaddr  amp  netmask      network  amp  netmask   def calcDottedNetmask mask       bits   0     for i in xrange 32-mask 32           bits     1  lt  lt  i      return   d  d  d  d      bits  amp  0xff000000   gt  gt  24   bits  amp  0xff0000   gt  gt  16   bits  amp  0xff00   gt  gt  8    bits  amp  0xff     Obviously from the same sources as above     A very Important note is that the first code has a small glitch - The IP address 255 255 255 255 also shows up as a Valid IP for any subnet  I had a heck of time getting this code to work and thanks to Marc for the correct answer

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Relating to all of the above  I think socket inet aton   returns bytes in network order  so the correct way to unpack them is probably  struct unpack   L

[python] How can I check if an ip is in a network in Python?

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