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What is the difference between 127.0.0.1 and localhost

Asked 2011-09-12T01:45:41.870
243

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?

sockets network-programming dns localhost
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2 Answers

69

Wikipedia sums this up well:

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.

answered 2011-09-12T01:52:14.840
11

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.

answered 2011-09-12T02:14:00.383

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