Problem with postfix

I describe my problem …

I have a server with Ubuntu 10.04 server has 2 network cards, 2 ips fixed external (Internet)
Have you installed: apache2, bind9, mysql 5.1, php 5.3 and postfix …
On this install webmin for ease of administration.
2 domains are configured, a. Com and. Info, each on a different ip, dns are configured (I think it well), in short up there is all barbarian, the problem is postfix …
When sending an email from domain1 (configured in the ip1) the email comes from ip1 … when sending an email from the domain2 (configured in ip2) email ip1 also goes by the … This is important because some emails do not get why some servers check the reverse dns.
The idea is to properly configure this for each domain to work with the IP that is related to MX.


All emails (and all traffic in general) will go out of the server using the default gateway, which is generally the primary IP address on your server.

It’s not possible to configure Postfix to send some emails out using one IP, and other emails out with a different IP.

However, this typically isn’t a problem; shared hosting servers commonly have many IP addresses, but send email out via just one.

Remote servers shouldn’t be checking that reverse DNS of the “From” address matches the primary IP of the sending server… it’s quite common for that not to be the case.

But, you would want to make sure that the primary IP does have a reverse DNS entry, and that should match the hostname of the server.

If the hostname of your server doesn’t match the reverse DNS of your primary IP, that can occasionally cause problems.


Hello Eric, thanks for response… i configure the reverse dns for my primary ip, but i still have problems, in my ofice need to send emails from domain2 to other servers (customers and partners), but these emails are not coming properly in some cases, sometimes not coming …
Is there any way to configure postfix (multiple instances) or configure the instance to correctly separate domains with their ip?..
Thank you… greetings…


Postfix will always send out email from all domains on your server using the same IP address. Normally, such a setup works well, so if that’s not working for you, we may need to dig into what’s going wrong there.

One thing you may want to do is review the mail logs whenever you send out an email, and see if any errors are showing up in the logs.

The mail logs are in /var/log/mail.log.


my postfix works fine, but does not do what I need …
I need every domain / ip configured to run for every domain / ip … if I send an email from the domain / ip x that email out by that domain / ip and not the primary ip …

Yup, I understand what you’re asking… but that’s unfortunately not possible :slight_smile:

It is not possible to configure Postfix to send some emails out using one IP, and other emails out with a different IP.

All emails will go out on the same IP address.

Sorry, but there’s no way to configure Postfix to do that.


Hello, i investigate some forums… and I found that with multi instances of postfix, this could be done … anyone ever did? know how?
Any forum, help, tutorial will be welcome.
Greetings and thank you very much