Author: Martin D Kealey Date: To: exim-users Subject: Re: [exim] SMTP transport interface IPv4/IPv6
> > Kai Bojens <kb@???> wrote: > But, then again there is an explicit virtual interface with that IP on my
> server Host A:
>
> ens3: IPv4 & IPv6
> ens3:402: 1.2.3.4 (IPv4 only)
>
> I would have that thought that exim then chooses ens3:402 for outgoing
> mail, but it decides to use ens3 and IPv6. Is there any way to change this
> behaviour?
>
Assuming you're on Linux...
Linux networking simply doesn't work the way that the ifconfig command was
designed to support, back in the 1980's. Instead the "ifconfig" command is
lies to you when it shows "virtual interfaces".
Look closely at the output of "ip addr list"; you won't see any virtual
interfaces, because they're not real, and I don't just mean "not hardware".
I mean there is no entity in the kernel that corresponds to what you see as
a virtual interface.
When Exim asks the Linux kernel for the list of interface names, it gets
given the real interface names.
I suggest using "ip" rather than "ifconfig" so that you see the true state
of your networking configuration ç
If you want Exim to bind to a specific address, that's plausible; I don't
know if it already offers that option but if it doesn't it's not a big job
to add it.
