Reverse DNS Lookup Question

Hello everybody! Here is my question:

Customer has its own in-house on-site mail server. The reverse DNS lookup shows the customer's ISP (GTE) rather than the customer's name.

Some anti-spam softwares around are bouncing non-spam e-mails from my customer, because the reverse DNS does not contain the customer's name.

Would there be any adverse effects or non-optimum ramifications if we changed the reverse DNS lookup to reflect the customer's name?

Would any other ISPs have problems receiving (non-spam) mail from my customer if we did this reverse DNS lookup change?

Any web sites you can refer me to?

All help is appreciated.

Thanks,
Hedda Lora

First your ISP (or whoever controls the reverse lookup) has to delegate authority for that IP to your name servers. Without them doing that, you cannot control what the reverse DNS lookup returns.

for shore. Read my sticky topic "Generic DNS References and tips" in the RDNS post. It should help educate you to the situation.

Thank you both for your responses.

I don't need to find out how to go about modifying the reverse DNS; rather, I just need to confirm that if we do change the reverse DNS so that it now contains the customer's mail server domain name (rather than the ISP's), there will be no unhappy ramifications (such as would any other ISPs for any reason bounce e-mails from the customer's mail server?).

I had a look at the link you provided, SilentRage, but I admit I couldn't find what I was looking for.

Basically all I really need to know is this: If we modify the reverse DNS lookup so that it now contains the name of the actual mail server (rather than the ISP's domain name), will other ISPs reject our e-mails ?

I appreciate any help on this.

Thanks,
Hedda Lora

no, it should be fine. I only pointed you at the post just to be sure we're on the same page as to how you need to make sure your mail server isn't rejected based on RDNS.

>> will other ISPs reject our e-mails ?

Like SilentRage said, NO. Though you can be rejected for many other reasons. Having a mismatch RDNS isn't at top 10 at all.

Here's a list for you:
1) you're direct spam source
2) your IP is unclean (been previously blacklisted since, blame that on yourself for choosing the wrong ISP, don't blame your ISP though)
3) broken reverse DNS ***most important*** (your RDNS better returns something, if it's null, don't run a mail server)
4) misconfigured DNS (check rfc-ignorant.org)
5) open relay
6) Running open proxy server
7) virus/worm infected

Thank you both for your help.

Cheers,
Hedda Lora