Receiving mail for specific addresses from few domains

[Argetlam]

Hi,

The following problem occurs:

I have set up a SBS server with a few user accounts.
Some of these accounts are unable to receive mail from (again) a few external domains.
One of these domains forwarded me the error they receive on their SMTP:

mail.XXX.org[XX.XX.XX.XX] timed out while sending RCPT TO>

This doesn't happen for all external domains, only for a few...

Can anybody point me in the right direction?

With kind regards,

Argetlam

SysAdmin

 

[ShackDaddy]

This sounds like connection dropping, and this is usually because your server is using RBLs as part of an anti-spam solution and is dropping connections from servers that match a certain profile. If you have RBLs in place, you may be subscribing to one that is two aggressive.

Are you sure that those same domains ARE able to send email to other accounts on your server? If they are, then RBLs are n't the problem.

Dave Shackelford
Shackelford Consulting

 

[Argetlam]

@ShackDaddy

There are no RBL's in place.
And yes, these domain's are able to send mail to other recipients on our server...

We've tried several things, like changing the mailaddress to no longer have .'s in it, without any success.

I've performed another test...
On

http://www.zonedit.com/smtp.html

there is the possibility to send a testmail to any server, with the additional feature of impersonating any sender you want.
So I tried to send an email to the recipient on our server and I filled in an email-address from the domain that usually fails. An guess what??? The mail arrives as it should...

Now somebody mentioned to me there might be a problem in the communication between mailservers when a mailaddress contains dots and that there should be a solution.
That person sadly enough did not provide me the solution.
Does this sound plausible?


With kind regards,

Argetlam

SysAdmin

 

[ShackDaddy]

I've never heard of a problem with email addresses that use dots. Many Fortune-500 companies use that address formatting, so I doubt that it's related.

What anti-spam measures do you have in place, on your server, on your workstations, and in Outlook?

If the connection failed on "RCPT TO" it sounds like your server didn't like the reply address that the remote sender used and dropped the connection...but you said you used that same reply address with the ZoneEdit test?

Can you go to DNSStuff.com and run a basic DNS health test against your domain and see if any problems show up in the MX section?

When you change some of your email addresses, do you actually CHANGE them, or do you create new, alternate addresses? I recommend doing the latter. It could be if you are CHANGING the addresses and then immediately testing, local server recipient filtering may be blocking addresses that aren't in the directory and your changes may not have showed up yet. I'm just guessing here. I typically just add additional SMTP addresses to a users email addresses rather than changing the existing ones.

Dave Shackelford
Shackelford Consulting

 

[Argetlam]

The "problem" with dots in emailaddresses doesn't sound plausible to me either, but I was just checking...

There are no anti-spam measures in place at this moment on the server itself. On Outlook there's McAfee installed.

And yes, in the ZoneEdit test I used the exact same reply address.

When I change a user, indeed I add a new alternate address.


With kind regards,

Argetlam

SysAdmin