Send e-mail from two different domains / IP addresses

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julian_julian
Posts: 3
Joined: Thu Jun 21, 2007 1:29 pm

Send e-mail from two different domains / IP addresses

Post by julian_julian » Thu Jun 21, 2007 1:35 pm

Hello, can I send e-mail from two different IPs?

I am sending mail by using my IP address which has set a reverse DNS record to my domain name.

I want to send e-mail for one of my clients, I can get a new IP address with its own reverse DNS set to my client's domain name. The idea is that only my client's domain name and IP information (not mine) appears in the e-mail headers of the sent messages.

I still want to use the service for myself. So I would need to use it for both IP addresses at the same time. Is that possible?

How can I do that? Is there any configuration I have to change in MailEnable? If I go to SMTP properties, I see my domain is listed there. And in the Outbound tab I see that Outbound IP Binding can only be set to one IP address. Would I have to change that info temporary every time I want to send e-mail using the other domain name?

MailEnable-Ben
Posts: 5858
Joined: Fri Jan 16, 2004 6:49 am
Location: Melbourne

Post by MailEnable-Ben » Fri Jun 22, 2007 1:46 am

Hi, the advertised address in a transaction is not generated by the PTR record it is taken from the server domain you entered in the SMTP service. So you could change this over to the customers domain name details. Then you really can use any outbound IP you like for both domains as this will in normal operation not be seen by a remote server. Yes the remote server will do reverse lookups on the IP to ensure there is a reverse PTR record but your customer will never see this unless he knows what he is doing and goes looking.

You may like to look in the manual for IP binding on the inbound connections however as you can bind each IP to a post office on the inbound, which will probably help more.
Regards,

Product Services
MailEnable Pty Ltd

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moegal
Posts: 118
Joined: Mon Feb 09, 2004 10:30 pm

Post by moegal » Wed Jun 27, 2007 10:09 am

Ben, thanks for the reply.

Here is the issue. I have many domains on my server, some with the same IP and some with their own IP's. The ones with their own IP's are getting blocked at other servers because of SPF softfail. "(xxxxxxxx.com: transitioning domain of domain.net does not designate nn.nnn.nnn.nn as permitted sender) client-ip=nn.nnn.nnn.nn;"

The IP that is coming thru is the main IP address of my server but not the one for this client. How can I have my regular email be sent from my main IP address while those sites with dedicated IP addresses send mail with their IP addresses?

Thanks, Marty

moegal
Posts: 118
Joined: Mon Feb 09, 2004 10:30 pm

Post by moegal » Wed Jun 27, 2007 10:30 am

Ben, I did not have a ptr record for the account I am working on. I added it and changed the spf all to be -all instead of ~all. I'll do some testing on that and get back to this thread.

Marty

moegal
Posts: 118
Joined: Mon Feb 09, 2004 10:30 pm

Post by moegal » Wed Jun 27, 2007 10:54 am

The email gets kicked back as a hard fail with the following message.
*************
Reason: Remote SMTP Server Returned: 554 This server requires you to send from an IP address specified by the SPF for xxxxxx.net.
*************

This must be what the -all does. Any ideas?

Looks like I could add the IP to the spf record, but I was hoping the sites with dedicated IP's could send from their own IP addresses, while the other sites sent from the main IP address.

Marty

Marconius
Posts: 47
Joined: Wed Oct 11, 2006 6:55 pm

Post by Marconius » Wed Jun 27, 2007 7:09 pm

moegal, I don't think you can send from multiple IP's on the same server at this time. The outbound smtp can only be bound to one IP AFAIK.

However reading this post jogged my memory about another post I read some months back with a how-to on how to get different domains to show up on the outbound.

http://forum.mailenable.com/viewtopic.php?t=12641

That post has some info about spf that might help you too, so your mail can pass a spf check in a multiple domain hosting scenario.

-Marconius

moegal
Posts: 118
Joined: Mon Feb 09, 2004 10:30 pm

Post by moegal » Thu Jun 28, 2007 11:04 am

Marconius,

Thanks, I am trying it now with one domain and will let you know how well it is received.

One question though. Cyberbeach recommends the following:
v=spf1 a mx ptr mx:mydomain.com -all

Do I really want the mx twice in the string? Here is what I have right now for mine. MSN has recommended we remove ptr and change the ~all to -all. (Cyberbeach already has the -all but has ptr and mx twice.)

v=spf1 a mx:mydomain.com -all

Any input on the quality of the spf record.

Marconius
Posts: 47
Joined: Wed Oct 11, 2006 6:55 pm

Post by Marconius » Thu Jun 28, 2007 4:06 pm

Well, the mx twice in the string is actually not twice. It is just kind of covering his bases.

Let's say we have domian1.com and domain2.com.

The outbound smtp is setup as mail.domain1.com. That domain is setup properly with mx and probably an spf of:

Code: Select all

v=spf1 a mx -all
domain2.com's spf would want to be setup like this:

Code: Select all

v=spf1 a mx ptr:domain1.com -all
now what this really does when you make a change in the future it makes it a little more dynamic and things will continue to work while you make your changes all around. The first mx means mail is allowed to come from any mx record listed in the domain. The ptr is probably not really necessary as it is relying on dns lookups and if the host has a ptr with the same domain name at the end. The second mx is listing another domain's mx records that you allow mail to come from. So in this case for domain2 you allow domain1's mx records to send mail for domain2. So those 2 mx's mean different things so they aren't really twice. The way I have mine is setup a little different.

I have mine setup is on the first domain I have it setup like the above.

Code: Select all

v=spf1 a mx -all
Then on all my secondary domains I have:

Code: Select all

v=spf1 a mx include:domain1.com -all
So that way it allows mail from any a record, mx record, or if the mail comes from domain1.com and that spf is setup properly it will work as well. I think it is all a matter of personal preference really.

Here is a guide on syntax for spf:

http://www.openspf.org/SPF_Record_Syntax

That should give you some idea about what everything does in a record.

-Marconius

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