Email issues, relay failure

[Bender, Chris]

Hi Jon
Thanks. There aren't any firewalls between the devices but they are far apart. I can telnet from x to a and I can ssh from a to x. 

I think you are right in focusing on the connection time out from A to X , i  looked  on X for a service that isnt running
Which makes this fail but I am not sure 
Which services. I see postfix and sendmail running and I have restarted them. I never see mail delivery from A in mailog on X


Thanks

On Feb 25, 2012, at 1:03 PM, "Jon Radel" <jon at radel.com> wrote:

> On 2/25/12 10:26 AM, Bender, Chris wrote:
> 
>> 
>> On telnet w IP it says unable to connect.
> ...
>> Its weird that the delivery on A says deferred connection timed out but on tcpdump I see the port 25
> 
> 
> If you can't establish a TCP connection from A to your relay server on port 25, I'd expect all of the above.  If you can't establish a TCP connection to port 25 at all from A, I'd stop focusing on the details of the e-mail server on the relay machine (as they're likely to be beside the point) and start focusing on what is blocking the traffic from A. Have you audited all the firewalls involved?  To be really focused, if you see traffic (both ways) at the relay server when A tries to talk to port 25, but A is convinced that no TCP connection is established, either you're stomping on things at the relay server (do your attempts to telnet to port 25 fail immediately or just sit there for a good long time and then fail?), the reply packets from relay to A are getting mis-routed, or A is ignoring the packets coming in from the relay.  Can you ping from the relay to A?
> 
> There's a distinct difference between failure to establish a TCP connection (look to the network stuff) and the e-mail server giving you an error response rejecting your attempt to transfer mail or just quietly loosing the mail (look to the e-mail servers).
> 
> -- 
> --Jon Radel
> jon at radel.com
>