Reverse DNS does not work for a particular IP

209.143.0.75209.143.0.74

if I do nslookup for the above IP, both returned a valid domain, see below

C:\Documents and Settings\grchu01>nslookup 209.143.0.75

Server: ns1.fnsi.net

Address: 206.183.224.7

Name: rhombus.bright.net

Address: 209.143.0.75

but why if I turn on reverse DSN is says as following:

02/12/2003 11:50:07 AM SMTP Server [04C8:006E-06E8] Connection from [209.143.0.75] rejected for policy reasons. IP address of connecting host not found in reverse DNS lookup.

Any ideas?

Do you think some settings are not right on bright net’s DNS setup?

How does Domino do the DNS lookup?

Thanks!

Subject: Reverse DNS does not work for a particular IP

I’ve had some issues with this ‘feature’ also. I haven’t been able to nail it completely, but try some of the following in your testing…In your post you are only looking up the A record - perhaps Domino is looking for a valid MX record…

at the command prompt, type NSLOOKUP

type SET TYPE=MX

type domain.com

gather the info - you should have something similar to the following: (example is from my MX record)

cantire.com

Server: xxxxxx

Address: xxxxxxx

Non-authoritative answer:

cantire.com MX preference = 10, mail exchanger = mx1.cantire.com

cantire.com nameserver = NS3.BELLGLOBAL.com

cantire.com nameserver = NS5.BELLNEXXIA.NET

mx1.cantire.com internet address = 207.61.17.3

NS3.BELLGLOBAL.com internet address = 198.235.216.130

NS5.BELLNEXXIA.NET internet address = 209.226.175.236

For a reverse lookup to work, the connecting host must be identified in DNS with an A record, and the message headers in the inbound email have to match the MX record associated with the A record of the connecting host.

Subject: Reverse DNS does not work for a particular IP

I assume you’ve tried the reverse lookup from the Domino server? It looks like you did it in the test from your nameserver (of course, they could be the same machine…).

If not, a test from the Domino server would tell you more, since that’s the beast looking up the address of the incoming connections!

(Since the reverse lookup works from some machine, there shouldn’t be a problem on bright.net’s side…)

Lee Sweet