Re: [Vserver] localhost oddity on vserver host

From: Paul S. Gumerman <psg_at_cooldog.com>
Date: Mon 03 Jul 2006 - 15:35:44 BST
Message-ID: <44A92B40.7080609@cooldog.com>

Herbert,

This problem is on the *host*, not a guest.

I've verified that none of the guests on vhost3 (the box with the
problem) has anything to do with 127.0.0.1.

Also, on vhost3, sshd with explicit "ListenAddress" settings for the
host's ip as well as 127.0.0.1 will start and run without complaining
that it cannot bind to 127.0.0.1, but netstat doesn't show it listening
on localhost.

For the life of me, I cant figure this out ...

On vhost1 (the working box):

[root@vhost1 ~]# ping 127.0.0.1
PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.
64 bytes from 127.0.0.1: icmp_seq=0 ttl=64 time=0.039 ms
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.018 ms
64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.033 ms

--- 127.0.0.1 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2010ms
rtt min/avg/max/mdev = 0.018/0.030/0.039/0.008 ms, pipe 2

On vhost3 (the troublesome box):

[root@vhost3 etc]# ping 127.0.0.1
PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.
                <hit cntrl-C here>
--- 127.0.0.1 ping statistics ---
6 packets transmitted, 0 received, 100% packet loss, time 4999ms

Any thoughts?

Paul

Herbert Poetzl wrote:

>On Fri, Jun 30, 2006 at 08:51:58PM -0400, Paul S. Gumerman wrote:
>
>
>>In it's own thread now -- sorry for the unintentional hijack.
>>
>>I have two practically identical vserver hosts, named vhost1 and vhost3.
>>
>>They are both running kernel CentOS (2.6.14.3-vs2.0.1-rc5) x86_64.
>>
>>/etc/hosts on each one is essentially the same, and the routes look
>>good and essentially the same.
>>
>>The ifconfig output for both looks the same, and both show traffic in
>>and out of lo.
>>
>>
>
>this suggests that you 'assigned' some loopback ip
>(probably 127.0.0.1) to both guests, which will them
>allow to bind to that ip too
>
>this very likely results in two guests competing for
>that address, so some services will be able to bind
>others will fail ...
>
>
>
>>On vhost1, "ping 127.0.0.1" works as expected, and sshd can listen on
>>the localhost port 22, and can be used there (by freenx).
>>
>>On vhost3, "ping 127.0.0.1" *sends* packets, but shows 100% packet
>>loss. Also, sshd does not complain about listening on localhost,
>>but it doesn't show up in netstat's output, and it doesn't work on
>>localhost (freenx fails).
>>
>>Does anybody have any ideas? Unfortunately, vhost3 is a hundred miles
>>away, and one of the virtual servers is running an important mail
>>server, so I have to be careful. But vhost1 is here, and not so
>>critical, so I can experiment with it.
>>
>>
>
>basically I do not see a good reason for assigning
>127.x.x.x to a guest, but if you have to, then try
>to choose different ones, e.g. 127.0.0.2, 127.0.0.3 ...
>
>HTH,
>Herbert
>
>
>
>>Thanks,
>> Paul
>>
>>
>
>
>
>>_______________________________________________
>>Vserver mailing list
>>Vserver@list.linux-vserver.org
>>http://list.linux-vserver.org/mailman/listinfo/vserver
>>
>>
>
>
>
>
>

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Received on Mon Jul 3 15:36:20 2006

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