Postfix + multiple relayhosts

[warlock]

Hi Guys,

How do I configure postfix to deliver to multiple smtp relay hosts.
We have 2 internet connection on a WAN bonder, if 1 line goes down we'd like post fix to deliver to a secondary smtp relay host.

I have tried this
relayhost = smtp1.box.com and smtp2.box.xom

postfix: fatal: relayhost parameter setting must not contain multiple values: smtp.mweb.net smtp.vbmail.co.za

Is there an option to alternate for load balancing or at least for fail-over

Thanks
Guys

[yui72o]

You should check this tutorial :
http://souptonuts.sourceforge.net/postfix_tutorial.html
At 4.2 they configure /etc/postfix/main.cf

#...
transport_maps = hash:/etc/postfix/transport
#...

and at 4.5 (most usefull for you) is the configuration of multiple relays

# Contents of /etc/postfix/transport
#
# This sends mail to Gmail
gmail.com smtp:[smtp.gmail.com]:587
#
# Except mail going to the tape and closet server
tape.squeezel.com relay:[tape.squeezel.com]
closet.squeezel.com relay:[closet.squeezel.com]

Please note that I think it is not at all for any load-balancing but multiple relays for local mail (Don't think you can ever do that with postfix ...)

I hope this will help

[XoCine]

Maybe that question is ooooooooold but have some nice solution :-)

Well warlock, in searching of solution I did some googling but did not found solution sooo I turned off Google and enable a Brain++ :->

What we want? That Postfix connect to one of FEW hosts (relayhosts).

Welll, lets play with DNS :-)

In example do domain mysweetdomain.com lets make some A lines:

mxr IN A 192.168.1.121
mxr IN A 192.168.1.131
mxr IN A 192.168.1.141
mxr IN A 192.168.1.151
mxr IN A 192.168.1.161


Lets flush bind and what we have? Nice :-)

[root@anubis postfix]# host mxr.mysweetdomain.com
mxr.mysweetdomain.com has address 194.177.4.121
mxr.mysweetdomain.com has address 194.177.4.131
mxr.mysweetdomain.com has address 194.177.4.161
mxr.mysweetdomain.com has address 194.177.4.141
mxr.mysweetdomain.com has address 194.177.4.151

Standard roundrobin rulez :-D

Then only that little line in postfix/main.cf

relayhost = mxr.mysweetdomain.com

and Postfix relays with every of these ips in roundrobin style :-)

Maybe it does not work as failover but better have 3/5 relays working then none :-) 60% delivered mails at once, rest waits for some time

Simple and nice :-) Hace fun :-)