Ok this post is a two parter. First of all I've never assigned multiple IP addresses to a single physical network device in linux before. I know it can be done and I'd imagine it's pretty straight forward, but if someone could give me a few quick notes/pointers it would be much appreciated.

Now the second part (and why this is in the Server section and not Networking :P), I'd like to setup a Postfix mail server that utilized multiple domain names and multiple IP Addresses on a single server with a single network card.

In the past I've configured Postfix to handle e-mail for multiple domains, so that part shouldn't be too tricky. But is there a way for Postfix to bind each domain name with its own virtual ip address?

Any help would be much appreciated. Cheers!

First thought - have you thought about running multiple instances of postfix?

Second thought - why? If you have postfix listening on all addresses, and have MX records for each domain correct, and postfix set up as per normal multi-domain setup, why do you need to bind domains at the IP end? If it's a sending issue, I'm sure you could arrange for each domain to deliver via the relevant IP.

Yeah I'd agree with billmayday.

Have Postfix listen on all interfaces. Setup MX records to point to each IP for each domain. When mail is delivered, it should use that domains IP associated with it.

Thanks for the fast replies. LQ is the best!

Here's a little more info about our situation. My company has paying customers that sign up for monthly newsletters. We can send as many as 600,000 emails per day, and we're currently doing it through 6 physical Windows servers running MailEnable mail software.

ISPs are starting to crack down and are warning us that we'll soon end up on their black lists for spammers. Again this is legitimate mail, but we can't speak with anyone from companies like comcast or yahoo to be placed on any kind of a white list.

So the folks in charge were wondering if it would help to spread our mail load across more IP addresses and domain names. At the same time, they don't want to purchase more physical servers.

So I could either Setup 2 - 3 VM's per physical box, or I could do a single Linux installation and try to configure the MTA software to send email out through multiple domain names and IP addresses.

I'd like to assign up to 5 virtual ip addresses to the single network card that installed in the servers, and then configure postfix to send email for 5 separate domain names. We're hoping that spreading our mail load across multiple domains/ips that the ISPs will loosen up a little bit and stop threatening to black list us as a spammer.

Did that make any sense? :P

So it's sending? I don't know if you can load balance acoss smtp instances, but as mentioned, you could certainly run multiple postfix's. Virtual machines sounds like overkill

Can't say if that will necessarily help your problem.

I'm getting out of my depth here, btu maybe this helps

http://www.linux-foundation.org/en/Net:Iproute2

Your company may want to look into a possible commercial solution as well to help deliver email. Maybe look into PowerMTA, from http://port25.com

"Have Postfix listen on all interfaces. Setup MX records to point to each IP for each domain. When mail is delivered, it should use that domains IP associated with it."

Is this step working?

Thanks.