Wingate 5.2.3 Email delivery troubles

[Grokh]

Hi!
We have the following configurations in our LAN: workgroup (no local domain). Our business Email system is based not by our ISP - it is based by our hosting provider. We have a lot of Email addresses and the messages are collected on the mail server by our hoster and delivered to us through the ADSL connection and Wingate.
From time to time some our messages are not delivered to our correspondents. They are moved to the Sent folders on our mail clients, but do not delivered to our correspondents. In the History on WinGate I can see the following messages in this case - SMTP Remote: 0 messages delivered to the ...Email address.... These messages are from <system> and IP address - 127.0.0.2!!!
What my cause the troubles?

[adrien]

Hi

That IP address is the one WinGate uses for logging internal activity just to keep it separate from all other activity.

As for what is going wrong with delivery, the best way to find that out is to turn on debug logging in the SMTP server. That should show exactly what is happening.

Adrien

[Grokh]

Thank you for your answer.
I have carefully investigated the problem and have found the following:
From the mail servers some of our corrspondents we receive the following answer:
" A transcript of the session follows
* Beginning processing of domain lek.ru
* Domain MX record lookup succeeded
* Attempting connection to mx.lek.ru.<= 220 mx.lek.ru ESMTP succeeded => HELO frum <= 250 mx.lek.ru Hello frum [195.131.89.XXX] => MAIL FROM:<xxxxx@katera.ru> <= 250 OK => RCPT TO:<xxxxxx@lek.ru> <= 550 Reverse lookup failed"
...
Who is responsible for this error - we or our provider? Because I see in delivery failure message that our internal IP-address is visible in message header:
"<= 550 Reverse lookup failed
----------------------------------------------
Your message reads (in part):
----------------------------------------------
Received: From favouriteiv (unverified [192.168.XXX.XXX]) by SMTP Server [192.168.XXX.XXX] (WinGate SMTP Receiver v5.2.3 (Build 901)) with SMTP id <0000001116@sailboats.ru>; Fri, 30 Jul 2004 14:10:48 +0400
Return-Receipt-To: "Arthur D. Grokhovski" <xxxxxxx@katera.ru>
From: "Arthur D. Grokhovski" <xxxxxx@katera.ru>
To: <xxxxxx@lek.ru>
Subject: Test"
...
What should we do?
Thank you for the support. Please excuse me for my bad English...

[Grokh]

Thank you for all for support. I have disabled SMTP server in WinGate and started SMTP service with "outbound to ISP SMTP server" option.
Everything is working veru well now.

[adrien]

That 550 error is coming back from the server you are trying to deliver to.

I imagine it is because it is having trouble doing a reverse lookup on your IP address?

I wouldn't have thought moving to another delivery server would have made any difference. This is happening prior to your server delivering any part of the message itself.

In that case, I would check in the WinGate mail settings for what your fully qualified domain name is set to. This is the only thing that could possibly be different, and it is possible the other server is trying to validate this.

Note that the HELO line is

HELO frum

. That means that your server is saying it is "frum". If you enter here instead the fully qualified name of your server, that could help.

Adrien

[Grokh]

Thank you.
I have changed first "frum" to "frum.katera.ru". The setting "frum" was incorrect of course - that was our problem.
Our ISP says that our IP-address 195.131.89.XXX has a reverse DNS record.
I should say some more about this problem. We cannot delivery the mail to the xxxxxx@lek.ru from any PC in our LAN and any addresse. But we can delivery the mail to this domain from the "frum" PC - that is the PC, on which WinGate is installed.
After we have disabled the Wingate SMTP server an enabled the using of our ISP SMTP server, we do not have described problem anymore.

[adrien]

ah ok.

You can get WinGate to deliver mail to your ISP server if it fails delivery directly. WinGate 6.0 does this a lot better than previous versions.

Also, if it might help to deliver to some domains, WinGate 6.0 allows you to specify a username and password for delivery to specific servers.

Adrien

[Grokh]

OK. Thank you about the information about the WinGate 6.0.
Now our Email system is fully working but I want to understand why we have get the message "500 DNS reverse lookup failed"?
Because our ISP does not have the MX-record for our post domain?
Or because the server lek.ru has tried to lookup our internal IP addresses (like 192.168.XXX.XXX)? From the PC on which Wingate is installed every Email message is delivered without problems, we have the problems only by another PCs in our LAN...

[adrien]

From the transaction in the logs, you can see that that error was reported before your sender sent the DATA command, therefore before any email headers were transmitted.

Therefore it has nothing to do with the content of the message (including the headers containing your internal addresses), but can only be dependent on any of

a) the name in the HELO command
b) the from address in the MAIL FROM command
c) the recipient address in the RCPT TO command..
d) the IP address of your server.

These were the only commands that had been sent.

So, I am pretty sure that the server you are delivering to tried to verify your servers advertised name "frum", and did a reverse lookup on your servers IP, which is an ADSL address on your ISP.

I guess the only thing to figure out what the new server (the one you are now using) does differently to succeed where WinGate failed, would be to look at the IP packets, using a packet sniffer like NetMon, or CommView.

Adrien

[Grokh]

OK. Thank you for your answer.