Outgoing IP

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Outgoing IP

Udo Hortian
Hello,

If I understand correctly, the value of primary_hostname in the file
/etc/exim/exim4u_local.conf.inc is used as outgoing IP address if
MULTI_IP is NO in this file.

After installing exim4u on a host with primary_hostname a FQDN, say
FQDN1 that points to an ip address IP1 of this box everything worked
fine. Now I changed this value to another FQDN, say FQDN2 that points
to another ip address IP2 of this box. In the outgoing_ip field of the
domains table in the MySQL database also IP2 appears. But when sending
outgoing mails from the domains I configured in exim4u, IP1 is used for
the SMTP connection. What am I doing wrong? In principle I want that
outgoing connections are everytime made from IP2. Note that I use
MULTI_IP = NO.

Best,
Udo


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Re: Outgoing IP

Udo Hortian
Hello,

On Sun, Oct 03, 2010 at 04:27:16PM +0200, Udo Hortian wrote:
> If I understand correctly, the value of primary_hostname in the file
> /etc/exim/exim4u_local.conf.inc is used as outgoing IP address if
> MULTI_IP is NO in this file.
As my experience shows, this is not the case.
 
> After installing exim4u on a host with primary_hostname a FQDN, say
> FQDN1 that points to an ip address IP1 of this box everything worked
> fine. Now I changed this value to another FQDN, say FQDN2 that points
> to another ip address IP2 of this box. In the outgoing_ip field of the
> domains table in the MySQL database also IP2 appears. But when sending
> outgoing mails from the domains I configured in exim4u, IP1 is used for
> the SMTP connection. What am I doing wrong? In principle I want that
> outgoing connections are everytime made from IP2. Note that I use
> MULTI_IP = NO.
I found a solution for the problem. I set MULTI_IP to YES and I will use
the same outgoing IP address for every domain. The documentation says
that a unique ip address must be assigned to each domain. I do not
really see the reason for this. I think one should have a PTR entry for
every IP address that is used as an outgoing IP address in SMTP
connections and that the name appearing in this PTR entry should have a
A entry pointing to this IP address. But I do not see a technical reason
why a different IP address must be used for every domain.

Best,
Udo


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Re: Outgoing IP

gldickens3
Administrator
In reply to this post by Udo Hortian
On 10/03/2010 10:27 AM, Udo Hortian wrote:
 > Hello,
 >
 > If I understand correctly, the value of primary_hostname in the file
 > /etc/exim/exim4u_local.conf.inc is used as outgoing IP address if
 > MULTI_IP is NO in this file.

Hi Udo,

With MULTI_IP=NO, Exim4U will always connect using the PTR record for
the machine's default (primary) IP address and The primary_hostname will
be used as the server name in the HELO dialog.

 > I found a solution for the problem. I set MULTI_IP to YES and I will
 > use the same outgoing IP address for every domain. The documentation
 > says that a unique ip address must be assigned to each domain. I do
 > not really see the reason for this. I think one should have a PTR
 > entry for every IP address that is used as an outgoing IP address in
 > SMTP connections and that the name appearing in this PTR entry should
 > have a A entry pointing to this IP address. But I do not see a
 > technical reason why a different IP address must be used for every
 > domain.

Udo, you are absolutely correct.  As long each IP address used by Exim4U
in the Multi-IP configuration has a valid PTR record then the Multi-IP
configuration should work just fine and you can use the same IP address
for as many domains as you want.  The only reason why a different IP
address should be used for each domain is if you want each domain name
to be specifically advertised as the mail host name during the SMTP
connections.

FYI,

Gordon