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Exchange server smtp error 500 5.3.3 Unrecognized command

d3m00n
d3m00n asked
on
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Last Modified: 2013-11-30
Hi,

I have a problem with commonication between two Exchange servers 2003.

exAsrv-FWsiteA----VPN------FWsiteB----exBsrv

Where:
exAsrv - Exchange 2003
exBsrv - Exchange 2003
FWsiteA - Cisco ASA5505 ver 7.2(2)
FWsiteB - Cisco ASA5505 ver 7.2(2)

Problem is when I try to comunicate with both servers on port 25.

1.
a)From exAsrv.mydomain.local I can telnet to port 25 to exBsrv.mydomain.local, but I see:
220 ****************************************************************************
*****************************************
helo
500 5.3.3 Unrecognized command

b)From exBsrv.mydomain.local I can telnet to port 25 to exAsrv.mydomain.local, but I see:
220 ****************************************************************************
*****************************************
helo
500 5.3.3 Unrecognized command

From RFC I have only information which I don't understand, why command line to long???
      4.2.1.  REPLY CODES BY FUNCTION GROUPS

         500 Syntax error, command unrecognized
            [This may include errors such as command line too long]

2. Another test. I enabled possibilyty on both exchange servers to comunicate on port 252:
a) From exAsrv I can telnet to port 252 to exBsrv, but I see:
220 exBsrv.mydomain.local Microsoft ESMTP MAIL Service, Version: 6.0.3790.3959
ready at  Fri, 8 Feb 2008 14:43:58 +0100
helo
250 exBsrv.mydomain.local Hello [192.168.1.200]

b)From exBsrv I can telnet to port 252 to exAsrv, but I see:
220 exAsrv.mydomain.local Microsoft ESMTP MAIL Service, Version: 6.0.3790.1830
ready at  Fri, 8 Feb 2008 14:45:07 +0100
helo
250 exAsrv.mydomain.local Hello [192.168.0.17]

On the site B exchange server is available from outside as a main server, however I want to
set up replication of both server. But now it is not a problem.

I checked configuration on both cisco routers:
1. NAT rules are setup correctly.
2. I disabled ESMTP inspecion on both sides.

Trraffic seems like is going correctly.

3.
a) Test telnet from host1B.mydomain.local(winXP) to exAsrv.mydomain.local to port 25.
220 ****************************************************************************
*****************************************
helo
250 exAsrv.mydomain.local Hello [192.168.0.23]

b) Test telnet from host2B.mydomain.local(GNU/Linux) to exAsrv.mydomain.local to port 25.

Connected to 192.168.1.200 (192.168.1.200).
Escape character is '^]'.
220 *********************************************************************************************************************
helo
250 exAsrv.mydomain.local Hello [192.168.0.5]

c) Test telnet from host2B.mydomain.local(GNU/Linux) to exAsrv.mydomain.local to port 252

Connected to 192.168.1.200 (192.168.1.200).
Escape character is '^]'.
220 exAsrv.mydomain.local Microsoft ESMTP MAIL Service, Version: 6.0.3790.1830 ready at  Fri, 8 Feb 2008 15:17:04 +0100
helo
250 exAsrv.mydomain.local Hello [192.168.0.5]

d) Test telnet from host3B.mydomain.local(WinXP x64) to exAsrv.mydomain.local to port 25.
220 ****************************************************************************
*****************************************
helo
500 5.3.3 Unrecognized command
e) Test telnet from host3B.mydomain.local(WinXP x64) to exAsrv.mydomain.local to port 252.
220 exAsrv.mydomain.local Microsoft ESMTP MAIL Service, Version: 6.0.3790.1830
ready at  Fri, 8 Feb 2008 14:45:07 +0100
helo
250 exAsrv.mydomain.local Hello [192.168.0.32]


Does one of you see any regularity as I don't.

Where can be a problem?

I think that somwhere in Windows, but don't see any regularity.
Please note I tested it when software FW are disabled on both sites.

Thank's for any suggestion.


Comment
Watch Question

Commented:
have you tried opening a command prompt on each of the servers and entering

telnet localhost 25

what reply do you get?

Author

Commented:
When I telnet on both servers like follow:

exAsrv
telnet 127.0.0.1 25
telnet 127.0.0.1 252

exBsrv
telnet 127.0.0.1 25
telnet 127.0.0.1 252


I see only black window with cursor on the top on the left hand side.

Author

Commented:
I've just check on onother my mail (Postfix) server:
telnet 127.0.0.1 25
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
220 mail3.externaldomain.com ESMTP ready
helo
501 Syntax: HELO hostname
helo domain.com
250 mail3.externaldomain.com

And I got reply with code 250 - so it is great, but I don't know where can be a problem on Excahnge servers.

Commented:
Can you confirm that the SMTP service is running on each of the servers

Author

Commented:
Yep. On both servers SMTP services are running.

Author

Commented:
Sorry for mutliple posts but I want to add as much as possible information.
According to:
telnet localhost 25
telnet localhost 252

on both servers I can telnet but I don't see any information only black window with cursor on the top on the left hand side.

When I type Enter I am goingback to command line.

Commented:
OK

when in the blank telnet screen, what happens if you type quit and press return.

Author

Commented:
On both servers when I:
telnet localhost 25

I am "logged" in and whatever character I type I am goint back to command line like:

C:\Documents and Settings\Administrator>



Commented:
strange

Do you have any firewall software installed on the servers? What version of windows are you running?

Author

Commented:
I think that we are on good way.

I checked on another Exchange server:
telnet localhost 25

and:

220 domain3.com Microsoft ESMTP MAIL Service, Version: 6.0.3790.1830 ready at  Fr
i, 8 Feb 2008 16:17:44 +0100
helo
250 domain3.com Hello [127.0.0.1]
quit
221 2.0.0 domain3.com Service closing transmission channel
Connection to host lost.
C:\Documents and Settings\Administrator>


Author

Commented:
I don't use any software FW. This one which is built in Windows is disabled.

exAsrv- Symantec Mail Security for Microsoft Exchange
exBsrv - F-Secure for Windows Servers.


I've just checked with both disabled and the same problem.

But on the exchange domain3.com I have also F-Secure for Windows Servers and with this enabled I am able to letnet to localhost. So probably there is something with windows settings wrong....hmmm...

Author

Commented:
On server exAsrv
telnet localhost 21
220 Microsoft FTP Service
quit
221

Connection to host lost.
C:\Documents and Settings\Administrator>

On the other I've not set up any other services yet, but for me it seems like something is wrong with Exchange, isn't it?

Commented:
Is there anything in the event log relating to exchange or SMTP errors?

Author

Commented:
FC01 the problem with telnet to localhost is solved.

telnet localhost  25.

220 exBsrv.mydomain.local Microsoft ESMTP MAIL Service, Version: 6.0.3790.3959
ready at  Fri, 8 Feb 2008 17:41:27 +0100
quit
221 2.0.0 exBsrv.mydomain.local Service closing transmission channel

220 exBsrv.mydomain.local Microsoft ESMTP MAIL Service, Version: 6.0.3790.3959
ready at  Fri, 8 Feb 2008 17:58:07 +0100
helo
250 exBsrv.mydomain.local Hello [127.0.0.1]
quit
221 2.0.0 exBsrv.mydomain.local Service closing transmission channel


Connection to host lost.

C:\Documents and Settings\Administrator>

Connection to host lost.

C:\Documents and Settings\Administrator>

I changed in the Servers->Protocols->SMTP->Default Virtual SMTP Server
in Properties

a) TAB: General
IP adress: from 192.168.x.x to All Unsigned
b) Button Advanced
Filter Enabled:
-Apply Sender Filter
-Apply Recipient Filter
-Apply Connection Filter
-Apply Inteligent Message Filter


And is OK now but still when talnet remotely I have an error 500 as above - but only for port 25

It doesn't make sense for me, do it?


Commented:
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Author

Commented:
Nope. In the evet viewer I have no errors.

Commented:
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