On 9/11/07, Jun Salen <nokijun at yahoo.com>
wrote:> >Hi List,
> >
> >My Mail/Proxy server has from time to time refuse
to> >accept accept network connection. If I restart the
> >network service, the service will again start to
> >accept connection but after some time will again
> >refuse connection. I use CentOS 4.5 with Squid,
> >DansGuardian, Postfix. Please can someone point me
> >what are the possible cause of this. Thank you.
>
> In addition to my posting above. When I make ping to
> other machine from the server, the server will again
> restore and accept connection. This is weird, so my
> temporary solution is to let the server continually
> ping other machine. Please help. Thanks again.
>
Ping is a very cheap and acceptable solution !
Anyway you'r certainly curious about the problem :-)
This is a problem about ARP request.
Maybe another machine with low activity share the same
IP or your
swith/hub
is badly configured !
You can use arping to detect any device with the same
IP and tcpdump
to look for arp request."arp -an" will show you the
arp table.
Regards
> junji
> aisalen.wordpress.com
> Linux Registered User #253162
>
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--
Alain Spineux
aspineux gmail com
-----------------------
When I do /sbin/arp -an in the server box it does not
contain entries for ip address where the server, it is
ok? I observed that when I ping the server from other
machine, it replies but from time to time displays
time-out. We use this server for our mail and proxy so
it is affecting us when time outs occur. Tsk tsk.
junji
aisalen.wordpress.com
Linux Registered User #253162
Send instant messages to your online friends http://uk.messenger.yahoo.com