SMTP Traffic Routing

Hello All,

I am wondering if anyone knows of a way to Route all outbound SMTP traffic through a specific IP address. Here is the Scenario:

I have a SonicWall with enhanced OS. It of course has a WAN IP address. It also has 2 IP addresses associated with the OPT port for public servers. I recently changed the IP address of my mail server from public to private. What i am looking to do is tell the SonicWall to take any SMTP (Or all traffic if that is easier) and send it out of one of the IP addresses associated with the OPT interface.

The reason for my doing this is that the MX record is pointed to one of the IP addresses of the OPT port. If I send mail out and it goes out of the IP that is associated with the WAN port (Different than the OPT IP) it is categorized as SPAM as the MX reverse look up is bad.

If anyone can provide any opinions or solutions it would be greatly appreciated.

Thanks,

Jason

Reply to
DigitalKid
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Tell whoever is doing this to stop being an idiot. The MX is the host supposed to *receive* mail. The MX record doesn't say anything at all about which host is sending out mail from this domain.

cu

59cobalt
Reply to
Ansgar -59cobalt- Wiechers

If I understand what you are saying, I can only ask...... Are you for real?

Reply to
Robert

Ansgar is right.

Please read RFC 974 / STD 10.

Yours, VB.

Reply to
Volker Birk

Yes.

However, if the OP must work around this he might try configuring the MX as the smarthost for his clients/MTAs and have the SonicWall send out all traffic from the MX on the OPT interface (if possible, I'm not familiar with SonicWall or the OP's network).

cu

59cobalt
Reply to
Ansgar -59cobalt- Wiechers

I understand what your issue is as we also have recently had this issue. For those who have previously replied you need the mx record to be attached to the emails or else companies such as aol and bt internet are unable to carry out a Rdns on the emails so classify it as spam and refuse to accept it. What you need to do is setup a NAT rule whereby the mx record ip address is transformed to your public address - then you need to tick the create reverse rule option - this will set it up to send mail from your internal to external ips using the mx record ip. Dont forget to apply the correct firewall rules as well. Should you have any problems feel free to email me as i know it can be a pain to solve.

Phil

DigitalKid wrote:

SMTP (Or all traffic if that is easier) and send it out of one

Reply to
Phil

Do they require that the rDNS lookup is successful (i.e. returns a name) or do they require that the rDNS lookup matches a/the MX record? The latter would be - as stated before - utter nonsense.

No. What you need to do - if you must work around this - is to use your MX as a smarthost for sending out mail, and make sure that outbound communication of the MX is NATed to the IP address given in the MX record.

Or, since the MX host has a private address, maybe you can change the MX entry in DNS to the public IP address and forward port 25/tcp to the MX.

cu

59cobalt
Reply to
Ansgar -59cobalt- Wiechers

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