mail sever unable to send mail to certain servers

[Drachenhunter]

Hello, I do tech support for an internet service provider and some of our customers are having problems mailing to a few servers:

Most of them get error 553 mailbox incorrectly specified. I myself have tried e-mailing the address that are returning this error and got the same error, I then tried using a hotmail account, they went right through. The only thing I found on google about it said something like the mail server(ours) wasn't allowing the mail to be relayed or something like that but we are able to recieve from them so I don't know if that means it's true or not. I've consulted my boss and he said it's probably a settings error on their(users) computers, even though I get the same error on my computer where I know the settings are right.

I don't know if this is the same issue or not but some other customers are recieving error 550 the mailbox was not found. I tried e-mailing the address and once again got the same error, are these two issues related?

I appreciate any ideas you guys can give me, Thanks.

 

[beerhunter2]

I've had this issue with one of my clients.

The 550 5.1.1 error means that a domain lookup failed (email domain could not be resolved to an IP number). This indicates a problem with the DNS server used by the email server. A 550 error is "host unknown".

What happened was that the receiving email domain was moved to a new ISP hosting service, but they did not cancel their service with their old service provider.

My client was with the same old service provider, so could only resolve with the old IP address which was incorrect.

 

[ChrisAC]

553 Requested action not taken: mailbox name not allowed
(E.g., mailbox syntax incorrect)

;-)

Chris.
**********************
Chris Andrew, CCNA, CCSA
chris@iproute.co.uk
**********************

 

[varuna]

try doing a nslookup of their domain, then search for mx records.

take the top priority one and note it's ip.

if you have access to a mail server you can play with, set a route up for the domain in question and point iot directly to the ip above.

try sending mail again

any good?
No Pain No Gain

 

[Drachenhunter]

well, it turned out that our server was on a blacklist, we got it taken care, and it seemed to work ok. Thanks for all the help.

 

[Drachenhunter]

I've also found that if you have people delete their outbox files and restart it helps with the "mail box improperly specified" error.

 

[creslan]

I've had a similar problem that specifically noted the IP of my gateway. I suspect a blacklist problem. How would I find out if we're on one?

 

[leploep]

try

http://www.dnsstuff.com

a VERY usefull site

in the middle on top there is a "spam database lookup" field.

rgds

Leploep