what to do after an IP change

[Robert]

Jeff Vian wrote:

<snip>

> 
> Also, when doing an install with FC2, FC1, and earlier RedHat versions,
> the hostname given during the install is (in my experience) usually also
> placed on the 127.0.0.1 line of this file.  I consider it a bug (but
> only a minor annoyance) that the assigned hostname is not placed on its
> own line with the assigned IP address, but in cases where there are
> multiple NICs it is harder to get it right so the present method may be
> best.  
> 
> Thus, multiple FQDNs on a line with a single IP address are not wrong. 
> They may be "not in good form" in your view but that is the way the
> /etc/hosts file is usually used. 
> 

I consider it a bug, too, and one of the first things I change whenever 
Anaconda hands me the reins to my new machine. It does make a 
difference, too, in at least one area. For the sake of argument, let's 
say you have a hosts file that looks like this:
127.0.0.1 localhost localhost.localdomain fred fred.localdomain

When you ping fred, you get something like this:
[root at fred rj]# ping fred
PING localhost.localdomain (127.0.0.1) 56(84) bytes of data.
64 bytes from localhost.localdomain (127.0.0.1): icmp_seq=0 ttl=64 
time=0.047 ms

If you leave the ping running and run ifconfig a couple of times, you 
can see that the counters for the loopback interface, lo, is incrementing.

Now if you clean up the hosts file:
127.0.0.1       localhost.localdomain   localhost
192.168.1.8     fred.localdomain        fred

...and again ping fred, you get different results:

[root at fred rj]# ping fred
PING fred.localdomain (192.168.1.8) 56(84) bytes of data.
64 bytes from fred.localdomain (192.168.1.8): icmp_seq=0 ttl=64 
time=0.058 ms
64 bytes from fred.localdomain (192.168.1.8): icmp_seq=1 ttl=64 
time=0.045 ms

This time, the ethX interface at 192.168.1.8 is being hit and the 
counters for the ethX interface are incrementing.
This is the result I expect when I ping myself.
Besides that, it's MY machine and that's how EYE want it to be! ;-)
(I also want this &%#@* ASUS m/b to go up in a puff of smoke but that's 
another matter altogether.)



-- 
You can fool some of the people some of the time,
and some of the people all of the time,
and that is sufficient.