OT: difficulty with moving server

Steve Campbell campbell at cnpapers.com
Thu Apr 15 19:23:22 IST 2010

Yep, I did. Obvious is usually where the problem lies.

The problem is solved. It was an ancient switch that had an ancient ARP 
table that wasn't even supposed to be caching arp.

Thanks for the help.


Eduardo Casarero wrote:
> 2010/4/15 Steve Campbell <campbell at cnpapers.com 
> <mailto:campbell at cnpapers.com>>
>     I'm trying to move one of our servers behind one firewall to
>     another. I can't figure out what might be cached that prevents a
>     smooth move. The mailserver is running a caching dns server, but
>     the public IP for the mailserver is being moved to the new
>     firewall, so I don't think it's DNS causing the problem.
>     It appears that when I have the machine moved, after stopping MS
>     (along with sendmail), the firewall accepts a telnet on port 25 to
>     another domain, but either the firewall or sendmail doesn't
>     receive or accept the returning packet. I get nothing in my
>     firewall logs for denials. Any arp tables are flushed that are in
>     front of the mailserver and firewall. I do believe I discovered
>     that sendmail retains routing information to it's default gateway.
>     A check on the firewalls indicate the proper public IPs have been
>     removed or installed. Mail travels into the server from the public
>     lan and is sent and received behind the firewall. It just won't
>     leave through the firewall to the public network.
>     Does anyone know of anything I might be overlooking from the
>     mailserver's point of view that might be cached and hanging
>     around? A reboot didn't solve anything for me, and I have similar
>     mailservers behind the new firewall with the same set of firewall
>     rules.
>     Thanks for any ideas and sorry for the OT.
>     Steve Campbell
> I dont want to sound obvious, but did you change the default gateway?

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