List of DNS errors... can anyone show me how to fix? 1

[sushi600]

Hi All,

Running W2K on two servers, one primary DNS, one secondary.
Using tools on dnsreport.com, I think I have it almost setup correctly. However, I received two "warnings" and was hoping someone here could show me how to fix them.

1) WARNING: One or more of your mailservers claims to be a host other than what it really is (the SMTP greeting should be a 3-digit code, followed by a space or a dash, then the host name). This probably won't cause any harm, but is a technical violation of RFC821 4.3.

mail.host1.com claims to be host host2.com.

Both hosts have their own zone's in W2K DNS setup, though they share the same IP address (want to nameserve for multiple domains using one server). I mainly do not want anyone to know host1.com is related to host2.com.


2) WARN: One or more of your mailservers does not accept mail in the domain literal format (user@[0.0.0.0]). Mailservers are technically required RFC1123 5.2.17 to accept mail to domain literals for any of its IP addresses. Not accepting domain literals can make it more difficult to test your mailserver, and can prevent you from receiving E-mail from people reporting problems with your mailserver. However, it is unlikely that any problems will occur if the domain literals are not accepted.

mail.host1.com's postmaster@[123.456.78.9] response:
>>> RCPT TO: <postmaster@[123.456.78.9]>
<<< 553 We do not relay non-local mail, sorry.

I am running Mercury Mail Server. I do not want people being able to use my server as a spam server, so I was told to disable relaying. Any suggestions?

Thanks in advance.

 

[No1shome]

You are OK on both these counts.
The first is telling you that your mail server does not answer to the name you have it DNSed to. This is quite common with virtual hosts. You server seems to echo the name domain.com in the SMTP banner when it is DNSed to mail.domain.com. Nothing to worry about.

The second issue is great too. It is recommended by many anti-spam sources not to accept to user@123.456.789.0 as this can be exploited on some servers by spammers.

There is nothing cited here that will have any adverse effect on the operation of your mail server.

*Mick*

 

[sushi600]

No1shome,

Thanks a million. My first DNS server, so wanted to make sure everything was right.
Also, just wondering if you happen to know why the DNS Management console for my two servers look different under the Reverse Lookup Zones.

i.e. assuming ip address 111.222.333.444

One shows &quot;333.222.111.in-addr.arpa&quot;
the other shows &quot;111.222.333.x Subnet&quot;

Reverse lookup seems to fail on the first one. However, I cannot clean out any of the reverse lookup entries.

 

[sushi600]

Sorry, forgot to mention that not only am I unable to clear out the Reverse Lookup Zone to redo it, I also have a folder called Cached Lookups that I cannot remove (I have set my server to forward to two other DNS servers).

Best Regards

 

[GlenJohnson]

A reverse lookup is just that. A forward lookup takes a name and tells you the ip address. A reverse lookup takes an ip address and gives you a name, which is why it's called a reverse lookup.

Glen A. Johnson
Johnson Computer Consulting
MCP W2K
glen@johnsoncomputers.us


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[sushi600]

Hi Glen,

It's just that on the first server, with Reverse DNS zone's that look like 333.222.111.in-addr.arpa fail the reverse DNS lookup test at dnsreport.com -- however, the second one with 111.222.333.x Subnet zone comes out OK. I checked and they map out to the correct names.