Recipient address rejected: User unknown from external emails only
We manage a company that is using SBS2003 with Exchange 2003 and we just created 2 new accounts through the SBS wizard which created email accounts for them. When anyone from outside the company tries to send them and email we get an error of "Recipient
address rejected: User unknown." I have also tried by telneting directly to their server from the outside and get the same error. Telneting internally it works as does all internal emails to and from the user. The user can also send out. The only failure
is incoming to this new user and new test user. They don't go through any spam filtering service and so far I have been unable to locate any AV or locally installed spam filter.. Any suggestions?
August 22nd, 2012 5:19pm
On Wed, 22 Aug 2012 21:05:49 +0000, C-M wrote:
>We manage a company that is using SBS2003 with Exchange 2003 and we just created 2 new accounts through the SBS wizard which created email accounts for them. When anyone from outside the company tries to send them and email we get an error of "Recipient
address rejected: User unknown." I have also tried by telneting directly to their server from the outside and get the same error. Telneting internally it works as does all internal emails to and from the user. The user can also send out. The only failure is
incoming to this new user and new test user. They don't go through any spam filtering service and so far I have been unable to locate any AV or locally installed spam filter.. Any suggestions?
Do you see the rejection in the SMTP protocol log? If not, it's not
Exchange thats the problem.
What's different between the "internal" and "external" address? Is
there some sort of SMTP proxy that needs to be updated with new
addresses?
---
Rich Matheisen
MCSE+I, Exchange MVP
--- Rich Matheisen MCSE+I, Exchange MVP
Free Windows Admin Tool Kit Click here and download it now
August 22nd, 2012 6:32pm
Hi,
If you create a new user with Exchange mailbox enabled in ADUC, can you reproduce this issue?
What is the NDR message?
thanks. Fiona Liao
TechNet Community Support
August 23rd, 2012 5:27am
On Wed, 22 Aug 2012 21:05:49 +0000, C-M wrote:
>We manage a company that is using SBS2003 with Exchange 2003 and we just created 2 new accounts through the SBS wizard which created email accounts for them. When anyone from outside the company tries to send them and email we get an error of "Recipient
address rejected: User unknown." I have also tried by telneting directly to their server from the outside and get the same error. Telneting internally it works as does all internal emails to and from the user. The user can also send out. The only failure is
incoming to this new user and new test user. They don't go through any spam filtering service and so far I have been unable to locate any AV or locally installed spam filter.. Any suggestions?
Do you see the rejection in the SMTP protocol log? If not, it's not
Exchange thats the problem.
What's different between the "internal" and "external" address? Is
there some sort of SMTP proxy that needs to be updated with new
addresses?
---
Rich Matheisen
MCSE+I, Exchange MVP
--- Rich Matheisen MCSE+I, Exchange MVP
I figured there had to be some type of spam filter or user filtering
but for the life of me I can't locate anything. When I telnet in this is
what I am seeing
220 mail.theirdomain.com ESMTP Postfix
EHLO test
250-mail.theirdomain.com
250-PIPELINING
250-SIZE 75000000
250-VRFY
250-ETRN
250 8BITMIME
Mail From:user@user.com
250 Ok
RCPT TO:testuser@theirdomain.com
550 <testuser@theirdomain.com>: Recipient address rejected: User unknown
Free Windows Admin Tool Kit Click here and download it now
August 23rd, 2012 11:26am
On Wed, 22 Aug 2012 21:05:49 +0000, C-M wrote:
>We manage a company that is using SBS2003 with Exchange 2003 and we just created 2 new accounts through the SBS wizard which created email accounts for them. When anyone from outside the company tries to send them and email we get an error of "Recipient
address rejected: User unknown." I have also tried by telneting directly to their server from the outside and get the same error. Telneting internally it works as does all internal emails to and from the user. The user can also send out. The only failure is
incoming to this new user and new test user. They don't go through any spam filtering service and so far I have been unable to locate any AV or locally installed spam filter.. Any suggestions?
Do you see the rejection in the SMTP protocol log? If not, it's not
Exchange thats the problem.
What's different between the "internal" and "external" address? Is
there some sort of SMTP proxy that needs to be updated with new
addresses?
---
Rich Matheisen
MCSE+I, Exchange MVP
--- Rich Matheisen MCSE+I, Exchange MVP
I figured there had to be some type of spam filter or user filtering
but for the life of me I can't locate anything. When I telnet in this is
what I am seeing
220 mail.theirdomain.com ESMTP Postfix
EHLO test
250-mail.theirdomain.com
250-PIPELINING
250-SIZE 75000000
250-VRFY
250-ETRN
250 8BITMIME
Mail From:user@user.com
250 Ok
RCPT TO:testuser@theirdomain.com
550 <testuser@theirdomain.com>: Recipient address rejected: User unknown
Ok I think I figured this out. They are using a linux firewall and using it as a smarthost relay... now to find out if anyone knows the password.
August 23rd, 2012 12:22pm
On Thu, 23 Aug 2012 15:12:36 +0000, C-M wrote:
>On Wed, 22 Aug 2012 21:05:49 +0000, C-M wrote: >We manage a company that is using SBS2003 with Exchange 2003 and we just created 2 new accounts through the SBS wizard which created email accounts for them. When anyone from outside the company tries to
send them and email we get an error of "Recipient address rejected: User unknown." I have also tried by telneting directly to their server from the outside and get the same error. Telneting internally it works as does all internal emails to and from the user.
The user can also send out. The only failure is incoming to this new user and new test user. They don't go through any spam filtering service and so far I have been unable to locate any AV or locally installed spam filter.. Any suggestions? Do you see the
rejection in the SMTP protocol log? If not, it's not Exchange thats the problem. What's different between the "internal" and "external" address? Is there some sort of SMTP proxy that needs to be updated with new addresses? ---
>Rich Matheisen MCSE+I, Exchange MVP
>--- Rich Matheisen MCSE+I, Exchange MVP
>
>I figured there had to be some type of spam filter or user filtering but for the life of me I can't locate anything. When I telnet in this is what I am seeing
>
>220 mail.theirdomain.com ESMTP Postfix EHLO test 250-mail.theirdomain.com 250-PIPELINING 250-SIZE 75000000 250-VRFY 250-ETRN 250 8BITMIME Mail From:user@user.com 250 Ok RCPT TO:testuser@theirdomain.com 550 <testuser@theirdomain.com>: Recipient address
rejected: User unknown
Postfix isn't Exchange. :-)
If they don't have Postfix set up to use LDAP then they're probably
doing some sort manual update to the file in the local_recipient_maps
parameter in the main.cf file.
---
Rich Matheisen
MCSE+I, Exchange MVP
--- Rich Matheisen MCSE+I, Exchange MVP
Free Windows Admin Tool Kit Click here and download it now
August 23rd, 2012 9:36pm
On Thu, 23 Aug 2012 15:12:36 +0000, C-M wrote:
>On Wed, 22 Aug 2012 21:05:49 +0000, C-M wrote: >We manage a company that is using SBS2003 with Exchange 2003 and we just created 2 new accounts through the SBS wizard which created email accounts for them. When anyone from outside the company tries to
send them and email we get an error of "Recipient address rejected: User unknown." I have also tried by telneting directly to their server from the outside and get the same error. Telneting internally it works as does all internal emails to and from the user.
The user can also send out. The only failure is incoming to this new user and new test user. They don't go through any spam filtering service and so far I have been unable to locate any AV or locally installed spam filter.. Any suggestions? Do you see the
rejection in the SMTP protocol log? If not, it's not Exchange thats the problem. What's different between the "internal" and "external" address? Is there some sort of SMTP proxy that needs to be updated with new addresses? ---
>Rich Matheisen MCSE+I, Exchange MVP
>--- Rich Matheisen MCSE+I, Exchange MVP
>
>I figured there had to be some type of spam filter or user filtering but for the life of me I can't locate anything. When I telnet in this is what I am seeing
>
>220 mail.theirdomain.com ESMTP Postfix EHLO test 250-mail.theirdomain.com 250-PIPELINING 250-SIZE 75000000 250-VRFY 250-ETRN 250 8BITMIME Mail From:user@user.com 250 Ok RCPT TO:testuser@theirdomain.com 550 <testuser@theirdomain.com>: Recipient address
rejected: User unknown
Postfix isn't Exchange. :-)
If they don't have Postfix set up to use LDAP then they're probably
doing some sort manual update to the file in the local_recipient_maps
parameter in the main.cf file.
---
Rich Matheisen
MCSE+I, Exchange MVP
--- Rich Matheisen MCSE+I, Exchange MVP
August 23rd, 2012 9:49pm
If no more questions on this thread, we may mark it as answered. Thanks.Fiona Liao
TechNet Community Support
Free Windows Admin Tool Kit Click here and download it now
August 27th, 2012 6:25am