Odd messaging config request
I host an environment with multiple domains, running on messaging 6 as an MTA.
One of the domain owners is complaining about being blacklisted because the @domain.com, when spam software tries to reverse lookup it, appears to come from a different one it originated from. They have proposed adding an additional NIC to the machine, and routing all of their mail through that single NIC, and setting up the all the DNS stuff externally to point to that.
So my question is is it possible to send, based on the domain on the envelope, messages out of different NICs? The customer has also asked if they could have a private instance that just binds to the New NIC.
Or am I going about this all wrong and should simply rewrite the headers based on domain?
[777 byte] By [
vudinga] at [2007-11-27 3:08:32]
# 1
Hi,
> One of the domain owners is complaining about being
> blacklisted because the @domain.com, when spam
> software tries to reverse lookup it, appears to come
> from a different one it originated from. They have
> proposed adding an additional NIC to the machine,
> and routing all of their mail through that single
> NIC, and setting up the all the DNS stuff externally
> to point to that.
This doesn't sound right to me.
No large organisation has the same upload IP address for email (MX record) as their outgoing MTA IP address. They are usually completely different systems (incoming MTA farm & outgoing MTA farm) or are behind some kind of load-balancing IP address (one frontend IP/multiple backend IP's).
Which blacklist is the domain being listed on? They may have misinterpreted the reason for being blacklisted.
Regards,
Shane.
# 2
Looks Like I'm fighting FCrDNS
$ nslookup -type=mx us.foo.com.
Server: dns.foo.bar.net
Address: 4.2.2.1
Non-authoritative answer:
us.foo.comMX preference = 10, mail exchanger = e4.ny.us.foo.com
us.foo.comMX preference = 10, mail exchanger = e5.ny.us.foo.com
us.foo.comMX preference = 10, mail exchanger = e6.ny.us.foo.com
us.foo.comMX preference = 10, mail exchanger = e31.co.us.foo.com
us.foo.comMX preference = 10, mail exchanger = e32.co.us.foo.com
us.foo.comMX preference = 10, mail exchanger = e33.co.us.foo.com
us.foo.comMX preference = 10, mail exchanger = e34.co.us.foo.com
us.foo.comMX preference = 10, mail exchanger = e35.co.us.foo.com
us.foo.comMX preference = 10, mail exchanger = e36.co.us.foo.com
us.foo.comMX preference = 10, mail exchanger = e1.ny.us.foo.com
us.foo.comMX preference = 10, mail exchanger = e2.ny.us.foo.com
us.foo.comMX preference = 10, mail exchanger = e3.ny.us.foo.com
....now do a fwd and ptr lookup on any of these will match....
$ nslookup -type=a e4.ny.us.foo.com
Server: dns.foo.bar.net
Address: 4.2.2.1
Non-authoritative answer:
Name:e4.ny.us.foo.com
Address: 32.97.182.144
$ nslookup -type=ptr 144.182.97.32.in-addr.arpa
Server: dns.foo.bar.net
Address: 4.2.2.1
Non-authoritative answer:
144.182.97.32.in-addr.arpaname = e4.ny.us.foo.com
