We have a mail server running Zimbra (ZCS 6.0.8). The server has 5 active public IP addresses in the same subnet. (.226
-.230
). I currently have A
records for each of these (host0.domain.com
..host4.domain.com
), with the main host.domain.com
of the machine pointing to .226
.
Our host has ended up being listed on the SORBS DUHL list (even though it's in a server farm). According to them you can get removed quickly by checking that your host has an MX
record, an A
record, and a PTR
record that points back to the hostname given in the MX
record.
I tried setting the PTR
records so that each of these addresses resolved back to their A
record (i.e. .228
had a PTR
to host2.domain.com
). However, I then got mail being rejected from other servers because when Postfix (under Zimbra control) sends out mail, it uses the main hostname for the HELO
- there doesn't seem to be any way to override it. So the PTR
records currently say host.domain.com
for all 5 IP addresses.
What's the correct way to handle this? Should I have an A
record for the domain that points to all the IP addresses (for round-robin handling)? I'm nervous of changes that could cause problems, so I'm wondering what the standard way to handle a multiple-IP-address mail server is.
HELO
setup requirespostfix-2.7-20091209
; ZCS is onpostfix-2.6.7.2z
postfix-2.7.1.2z
- hopefully when the final 7.0 is released it will then support theHELO
syntax