[NTLUG:Discuss] localhost vs "real" IP address

[Kenneth Loafman]

Chris Cox wrote:
> George Lass wrote:
>> Sorry, I got that backwards.  It should have read something like:
>>
>> ... how much more overhead in using the IP address for eth0 as compared to 127.0.0.1...
> 
> :)  Well.. that obviously varies.  But I'm not sure how quantifiable it is... anyone?

It really should not vary.  Both translate to an internal interface.

traceroute to 192.168.1.5 (192.168.1.5), 30 hops max, 40 byte packets
 1  neptune.local (192.168.1.5)  0.071 ms  0.032 ms  0.031 ms

and

traceroute to neptune (127.0.0.1), 30 hops max, 40 byte packets
 1  neptune.loafman.com (127.0.0.1)  0.072 ms  0.031 ms  0.031 ms

Both come up with 0.031ms on my machine.  One is going to an internal
'lo' interface, the other to 'eth0'.  I would imagine the difference
could be measured with enough repetition and measurement.  I doubt it
would amount to even a 0.1% difference.

...Ken