Sending to multiple email servers

[Ugo Bellavance]

> -----Message d'origine-----
> De : William Burns [mailto:William.Burns at AEROFLEX.COM] 
> Envoyé : 2 avril, 2004 19:56
> À : MAILSCANNER at JISCMAIL.AC.UK
> Objet : Re: Sending to multiple email servers
> 
> 
> Howard:
> 
> You're using postfix? I can't answer the question for that 
> application,
> but I know how to do it w/ sendmail.
> 
> First, to re-create your existing setup...
> You've got balanced MX records pointing to two MailScanner machines:
> 
> # cat named.mydomain.com
>  > @ IN SOA ns.mydomain.com. spambucket.mydomain.com. (
> ...
>  > IN NS ns.mydomain.com.
>  > IN MX 10 mailscanner1.mydomain.com.
>  > IN MX 10 mailscanner2.mydomain.com.
> 
> Next, you've got to create a subdomain for your downstream 
> mail servers.
> In this example, the subdomain will be mailboxes.mydomain.com.
> I don't know if your 3 mail servers are peers, or if one is 
> primary, and
> the other 2 only relays.
> I'll balance the MX records as if the second 2 servers are relays.
> 
>  >
>  > mailboxes IN MX 10 mailserve1.mydomain.com.
>  > IN MX 20 mailserve2.mydomain.com.
>  > IN MX 20 mailserve3.mydomain.com.
> 
> Now, aside from the relay configs that you'll need for sendmail, you
> have to do this:
> In the /etc/mail/mailertable file, add the following line:
>  > mydomain.com smtp:mailboxes.mydomain.com
> note: don't forget to build the resulting mailertable.db file.
> 
> when sendmail sees this, it will do an MX lookup against
> mailboxes.mydomain.com in order to find out where to send mail for the
> domain mydomain.com.
> 
> There's also an interesting way (in sendmail) to avoid the MX 
> lookup by
> using square brackets like this: [mailboxes.mydomain.com]. That would
> mean "send mail to a machine named mailboxes" instead of 
> sending through
> the MX records for "mailboxes".
> 
> You might want to use that technique on mailserve2, and mailserve3 if
> they're relay machines. That way, you'd avoid some useless 
> DNS lookups.
> On mailserve2, for example:
> cat /etc/mail/mailertable
>  > mydomain.com smtp:[mailserve1.mydomain.com]
> 
> Now, if you hard-code the IP for mailserve1.mydomain.com into the host
> file for the mail-relay named "mailserve2", you wont need to 
> do any DNS
> queries to deliver mail from that machine.
> 
> I figure other MTAs should be configurable to work this way too.
> Hopefully that helps.


Yes, I think the same DNS setup, with a correct entry in the transport_maps file would do it... You might want to try that, Howard.

> 
> -Bill
> 
> Howard Yuan wrote:
> 
> >Hello all.
> >
> >I currently have my MailScanner set up to receive mail for anything
> >going to mydomain.com. Its configured to receive the email, 
> scan it for
> >viruses and spam, then send it off to my main mailserver, which
> >distributes the mail to my users. I have three mailservers 
> (in case one
> >goes down). I was wondering if its possible to set up the MailScanner
> >to...well, what I'm worried about is if my main mailserver goes down.
> >Then MailScanner will have no where to send the email. Normally, a
> >mailserver would scan through the mx records and go to the 
> next server
> >listed to try to send the email before it sets it aside for retry. I
> >would like MailScanner to do something equivalent, where it'll try to
> >send it to one mailserver, if that fails, to try another 
> one, and so on
> >and so forth before it gives up. Any ideas? Thanx in advance.
> >
> >Howard
> >
> >
> >
>