Email from my host got block from some anti-spam server
Hi all,
I have my exchange 2007 installed (single server environment, no edge server) behind a firewall.
The server uses a private IP 192.168.x.1, masquarade thru the firewall as mail.myhost.com.
so under mx record for DNS from internet, it shows mail.myhost.com IP.
Send/receive email is not a problem but there are few weird thing and I hope people can advise me on:
When I send message, it appears in the header the private IP number: receive from 192.168.x.1 (mail.myhost.com).
I guest this is the header from the exchange server because it believes it is its IP.
My question is: how can I make the header appear with my real IP for mail.myhost.com, not the private one. Did I miss-config my server?
Does this cause other server with spam filtering block email from my domain ? (they did not say what it is just say "spam reject")
Thank you in advance.
All Replies
- Hoang,
Do you do NAT on you firewall and does this IP-adres match the MX-record ? This could me a problem because some servers use reverse-dns to check if the sender is really who he says he is.
You can change the data that is send in the internet-header you should check the following document:
http://technet.microsoft.com/en-us/library/bb232136.aspx
Regards,
Johan Johan,
the header looks like this.
my_external_ip replaces my actual public IP address xx.xx.xx.xx
I think the problem is that the Exchange server report its host as 192.168.1.16 as it is its private IP.
I don't know there is a way to replace the line
Received: from mail.myhost.com ([192.168.1.16]) by mail.myhost.com
([192.168.1.16]) with mapi; Wed, 9 Apr 2008 16:47:22 -0700with the public IP instead. The internal IP showing in the header could be the problem.
Do you have the same header when you send email from your exchange server?
From Hoang Nguyen Wed Apr 9 16:47:21 2008
Return-Path: <hoangn@myhost.com>
Authentication-Results: mta412.mail.mud.yahoo.com from=myhost.com; domainkeys=neutral (no sig)
Received: from my_external_ip (HELO mail.myhost.com) (my_external_ip)
by mta412.mail.mud.yahoo.com with SMTP; Wed, 09 Apr 2008 16:48:42 -0700
Received: from mail.myhost.com ([192.168.1.16]) by mail.myhost.com
([192.168.1.16]) with mapi; Wed, 9 Apr 2008 16:47:22 -0700
From: Hoang Nguyen <HoangN@myhost.com>
To: "Hoang Nguyen (Yahoo.com)" <hoangmn@otheremail.com>
Date: Wed, 9 Apr 2008 16:47:21 -0700
Subject: testHoang,
No I have the following:
Received: from my_internal_hostname (my_external_hostname[my_external_ip])
So it does display the local hostname but not the local IP-adres.
Have you checked your NAT-settings ?
Regards,
Johan
- HoangMN,
You shouldn't have to worry about this. Whenever your server sends an email out to the internet, the server that will receive the email will be adding a "Received:" header that will contain your external IP for mail.myhost.com. So *all* of your emails that have been sent to the internet will have that header added to them by the receeiving mail server. This is an RFC requirement, so you can be sure it will happen if the receiver is using a "real" mail server.
---------
Roberto Franceschetti
http://www.logsat.com - Problem is some email servers are rejecting email as SPAM. They see the originating IP and domain as the internal ones. Since that doesn't match the public information, they think it's a spoof / fake / spam email, so they reject it.
How the heck do we configure Exchange to fix this? :( There is nothing to fix in Exchange. All mailers will include potentially unroutable ip addresses in their headers. That ip address the last SMTP gateway server uses to send to external SMTP mail systems has to be an valid, internet-routable IP address, or NATed on the firewall to one. If that isnt the case, then you need to fix that on your firewall.
If you post the entire actual header, we can point out where that is listed.
