Assuming the following is defined in .../hosts
:
127.0.0.1 localhost
What, if any, are the actual differences between using 127.0.0.1
and localhost
as the server name, especially when hitting processes running locally that are listening for connections?
This question is related to
sockets
networking
dns
localhost
There is nothing different. One is easier to remember than the other. Generally, you define a name to associate with an IP address. You don't have to specify localhost for 127.0.0.1, you could specify any name you want.
Well, by IP is faster.
Basically, when you call by server name, it is converted to original IP.
But it would be difficult to memorize an IP, for this reason the domain name was created.
Personally I use http://localhost
instead of http://127.0.0.1
or http://username
.
some applications will treat "localhost" specially. the mysql client will treat localhost as a request to connect to the local unix domain socket instead of using tcp to connect to the server on 127.0.0.1. This may be faster, and may be in a different authentication zone.
I don't know of other apps that treat localhost differently than 127.0.0.1, but there probably are some.
On modern computer systems, localhost as a hostname translates to an IPv4 address in the 127.0.0.0/8 (loopback) net block, usually 127.0.0.1, or ::1 in IPv6.
The only difference is that it would be looking up in the DNS for the system what localhost
resolves to. This lookup is really, really quick. For instance, to get to stackoverflow.com
you typed in that to the address bar (or used a bookmarklet that pointed here). Either way, you got here through a hostname. localhost
provides a similar functionality.
The main difference is that the connection can be made via Unix Domain Socket, as stated here: localhost vs. 127.0.0.1
Source: Stackoverflow.com