[ On Tuesday, November 20, 2001 at 01:02:56 (-0500), Peter Radcliffe wrote: ]
> Subject: Re: [Exim] double check DNS
>
> If my laptop, which can be connected to the net in any one of dozens
> of places, gets a network connection from somewhere new where I have
> no idea what the emerging IP address from being behind NAT will be
> (especially when it's dynamic and I have no idea what the IP/name is
> day to day) I'm supposed to find out and change my mail server config
> before sending mail ? Screw that ...
If you've got a _roaming_ private host, and if you cannot figure out how
to make this configuration learn its proper external hostname, then it
has absolutely zero business ever talking SMTP out through a NAT to the
real public Internet. Period. No if's and's, or but's.
You must always use a proper relay host in such a configuration. Your
DHCP server should, if it's configured properly, be handing you one or
more addresses of SMTP server(s) you must use to relay e-mail to the
public Internet.
> HELO/EHLO isn't reliable. No one with any sense cares about the name
> provided.
So you'd like to think. But you are wrong.
The SMTP client "MUST" send the canonical hostname for its source
address, or a literal representation of that address.
--
Greg A. Woods
+1 416 218-0098 VE3TCP <gwoods@???> <woods@???>
Planix, Inc. <woods@???>; Secrets of the Weird <woods@???>
