Subject: Re: [vserver] network issues with lo interface
From: "Michael S. Zick" <mszick@morethan.org>
Date: Sun, 22 Feb 2009 11:32:18 -0600

On Sat February 21 2009, Corin Langosch wrote:
> Hi again!
> 
> I migrated from vserver 2.2.0.6 (kernel 2.6.22) to 0.30.216-pre2772
> (kernel 2.6.26) and have another network issue. I have a daemon running
> in a guest and binding to 127.0.0.1:8002 (netstat -lnp shows correct
> output). A client running in the same guest now wants to connect to
> this daemon. The connection fails. Even testing the stuff with telnet
> fails.
> 
> I  checked the host, and found these dropped packets (because of my
> firewall):
> 
> firewall (dropped):IN=lo OUT=
> MAC=00:00:00:00:00:00:00:00:00:00:00:00:08:00 SRC=127.179.144.1
> DST=127.179.144.1 LEN=60 TOS=0x10 PREC=0x00 TTL=64 ID=2390 DF PROTO=TCP
> SPT=55160 DPT=8002 WINDOW=32792 RES=0x00 SYN URGP=0
> 
> I wonder why the system tries to connect to 127.179.144.1 although I
> typed "telnet 127.0.0.1 8002"? Is this a bug or a feature? ;-)
> 

In general, that is just the way "host local" is done in the network stack.
"host" here being the usage in network terminology.
Both "127.0.0.1" and the assigned machine IP address the same machine.
Call it a feature.

In the newer VServer setups, you have the *option* to give each "guest"
an "lo A.K.A: 127.0.0.0/8" interface.

So, more info needed:

what context where you in (VServer host or Vserver guest) when you 
typed the telnet command?

how did you configure the VServer kernel?  Isolated lo or not?

Mike
> Thanks,
> Corin
> 
> 
>