SMTP Issues?

[TwiceSliced]

We're running Exchange Server 2003 (SBS) and have an external spam filtering service. All server traffic is over our T1 line; all workstation web traffic is over a separate DSL connection.

Two common error messages have started popping-up recently:

1 - <domain.tld #5.5.0 smtp;550 <[email protected]> Relaying denied>

2 - SMTP Server Remote Queue Length Alert (on our local server)

The only recent change I can think of that might elicit such warnings is adding external DNS servers to our local DHCP settings in an effort to lighten the load on our server... I tried adding the external DNS server IPs to the local relaying whietlist, but no dice. Should I be contacting the external filtering service provider? What'm I missing?

Thanks.

 

[Digital-Vortex]

This might need some more info.

1. Are you sending mail out via the external spam service?
2. look at the email headers. what server are these coming from?

If they are coming from the spam servers I would assume its not setup properly, or your server is not authenticating to it.

If its from your server then your outgoing SMTP settings need to be looked at.

G

 

[YeOldeStonecat]

Yeah more info is needed.

From which end? Sending FROM the server? Or are these NDRs that people attempting to send TO the server get?

 

[TwiceSliced]

All mail is routed through a smart host run by the external service.

The first warning shows-up when trying to send from our server.

Both warnings are coming from our server.

 

[SJConsultant]

The only recent change I can think of that might elicit such warnings is adding external DNS servers to our local DHCP settings in an effort to lighten the load on our server... I tried adding the external DNS server IPs to the local relaying whietlist, but no dice. Should I be contacting the external filtering service provider? What'm I missing?

Thanks.

Was everything working before you made the changes? If yes then reverse the changes you made wait 24 hours and see if things return back to normal.

 

[TwiceSliced]

Was everything working before you made the changes? If yes then reverse the changes you made wait 24 hours and see if things return back to normal.

Yeah, that's the obvious final step if I can't get things working otherwise, but the current changes alleviate huge amounts of stress on our already overworked server. I was mostly just wondering if I was missing a step, like having the filtering service add their own DNS server IPs to some kind of domain-specific whitelist for relaying... Clearly, this is not my area of expertise

I'll revert to the previous settings if it turns-out that I've done everything correctly and there is no solution, but then I'll start getting DNS errors and interruptions in web traffic.