topic Re: Configure multiple relay hosts in Sendmail in Operating System - Linux

Configure multiple relay hosts in Sendmail

raver_1 — Sat, 12 Mar 2005 08:56:05 GMT

Hi!

May I know how do I go about configuring multiple mail relay hosts in /etc/sendmail.cf?

Thanks in advance.

Regards,
Jayce

Re: Configure multiple relay hosts in Sendmail

Ivajlo Yanakiev — Sat, 12 Mar 2005 11:45:31 GMT

Redhat do not use /etc/sendmail.cf
for config sendmail.
You must change sendmail.mc.
Every time when you restart your sendmail it will make sendmail.cf from sendmail.mc and all manula change will be lost :)

Re: Configure multiple relay hosts in Sendmail

raver_1 — Sun, 13 Mar 2005 05:29:39 GMT

So is it possible to have multiple SMART Relay hosts defined?
How?

Re: Configure multiple relay hosts in Sendmail

Vitaly Karasik_1 — Sun, 13 Mar 2005 09:09:04 GMT

1) it's right that the easiest way to configure sendmail it's using sendmail.mc instead sendmail.cf, but RH linux [at least RHEL 2.1 and 3.0] doesn't build sendmail.cf automatically from sendmail.mc during startup.

2) and regarding Raver question itself - AFAIK, we cannot define several relay hosts in sendmail config. But you may create local DNS server and define several IPs for the same hostname.
I mean - you can create several DNS records for your "smart_host" hostname.

Rgds,
Vitaly

Re: Configure multiple relay hosts in Sendmail

kcpant — Mon, 14 Mar 2005 00:49:56 GMT

Hi jayce,

In addition to Vitaly, I want to tell you is sendmail.cf is used in all distributions of Linux or other unix flavours, don't get confused with the first answer.sendmail.cf is a file of sendmail package, and it does not change it's behaviour for different OS. sendmail.mc is the macro definition file, from where you can define features and other inputs for your setup very easily, and then make sendmail.cf through it( m4 sendmail.mc > sendmail.cf , or other way ). and for your problem ( defining several smart hosts), Vitaly is right, you can't define more than one smart hosts, but you can make "virtual" DNS entries for this purpose.

Re: Configure multiple relay hosts in Sendmail

raver_1 — Mon, 14 Mar 2005 08:22:56 GMT

Thanks all for reply.

Cheers,
Raver

Re: Configure multiple relay hosts in Sendmail

Kyriakos_1 — Sat, 14 May 2005 13:32:25 GMT

Actually the previous answers that this is not possible do not seem to be entirely correct :-)

If you want to use multiple smart hosts then try the following in your mc file:

define(`SMART_HOST',`host1:host2:host3')

or in your sendmail.cf

DShost1:host2:host3

( The syntax is [mailer:]host[:host...] )