EXIM - fallback to smarthost

[Gary Stainburn]

Hi Ed

Long time no type ;)

On Thursday 06 October 2005 6:05 pm, Ed Wilts wrote:
> On Thu, Oct 06, 2005 at 04:44:30PM +0100, Gary Stainburn wrote:
> > My live server is Exim 3, but I'm in the process of updating to a
> > new box running Exim 4.
> >
> > I don't have a smarthost set and SMTP delivery is set direct as I
> > prefer this for both performance and logging reasons.
>
> You may prefer it but the target doesn't.  That's why your email is
> being blocked.
>
> > However, I have just chaanged ISPs and for some reason my IP
> > address range is on an RBL.
>
> "For some reason"?  Give us your IP address and we'll tell you why.
> There's a good chance that you're in a dynamic IP address range and
> that will be blocked by a LOT of hosts.

I have a leased line connection with a fixed IP subnet of 
80.193.83.129/25 (I think the netmask is right)

This should not have been included on a dial-up RBL.

>
> > Is it possible with both versions to configure it so that it tries
> > to deliver directly, but fall back to my ISP's SMTP relay if it
> > fails.
>
> I don't think so.  SMTP doesn't have an error for "we don't like your
> source address".  The transaction is being rejected but you really
> don't know why - different servers reject with different messages and
> error codes.

Okay. What I get back is SMTP rejection error 550: which is 
administrative rejection.  The explanatory text I get back with it 
states that it's been rejected because the source IP is on a RBL.

>
> What you can do with sendmail is to add mailertable entries for
> specific domains that will override the default smart host.

I think you can do similar with exim but don't know how.  However, I had 
hoped for it to be more robust and do it automatically if a direct send 
fails.

>
> Personally, I gave up and send all email through my ISP.

The problem with this is performance.  Even the techie at my ISP 
admitted that this would seriously slow down email, which I can't 
afford for my company.  For a long time we've done more emails than 
faxes, and now we're using email at least as much as voice phone calls.

>
>         .../Ed

-- 
Gary Stainburn
 
This email does not contain private or confidential material as it
may be snooped on by interested government parties for unknown
and undisclosed purposes - Regulation of Investigatory Powers Act, 2000