Like many other companies, our block of IP addresses is owned by our current
ISP. Thus our "real" host names are all *.nextlink.net. But we own our
domain name, and we are who we claim to be, so that is the source of our
"forging".

How do most people in a similar situation handle this? I did make a change
in the mail server's IMail registry settings to change the host name to
mail.uhsweb.com instead of the nextlink.net entry. I don't like seeing the
nextlink.net in all of our transactions. I prefer to see our own domain
name - our business name - whenever possible.

Joseph Marlin
Director of Information Technology
Unified Health Services

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of R. Scott Perry
Sent: Monday, December 31, 2001 10:48 AM
To: [EMAIL PROTECTED]
Subject: Re: [IMail Forum] Declude DNS report on IMail server



>I get a warning from the DNS report on www.dnsreport.com that implies that
I
>am out of compliance with RFC821 4.3.

That's correct.

>The report says "Mail server host name in greeting" and complains that my
>mail server identifies itself as mail.uhsweb.com.

No, the problem is reported as "mail.uhsweb.com claims to be host
SMTP."  The DNS Report gets "mail.uhsweb.com" from your MX
records.  However, when the DNS Report connects to mail.uhsweb.com, it says
that it is a host called "SMTP".

Specifically, a mail server is required to sending a "greeting" of "220"
followed by a space or a dash (the dash is used with multiline responses),
followed by the host name of the server.  For example, "220
mail.example.com SMTP server".  Yours responds with "220 SMTP Service
Ready".  According to the RFCs, your host name is "SMTP", which isn't a
valid host name.

Although IMail doesn't handle this properly (it sends "220 X1 ..."), the
response that you are showing isn't from IMail, so it sounds like a
firewall is interfering with the SMTP transaction.

>What is the problem with this

You're claiming to be something other than what you are -- essentially
forging information.

>and how can I change this -

That depends on what software/hardware is returning the response (it isn't
IMail).

Note, however, that IMail can't be configured to respond properly (it will
always report the host name as "X1", even if you make the registry change
to have your own greeting).

>or would I even want to?

Because you are not RFC-compliant, and it's possible that in the future
other servers might not accept your mail, assuming that you are a spammer
(since there is seemingly forged information).

>It sounds like it wants me to reveal the name of
>the server on my local network which handles my email.

That's what the RFCs require.

>I'm not too sure I want to do that - why help the hackers?

I don't think that it can help hackers in any way.

Also note that any hacker that connects to your mail server will know the
IP address of the mail server, and they can easily find out the host name
by doing a reverse DNS lookup on the IP address.  If you take out your
reverse DNS entry, you definitely will have E-mail dropped by some other
mail servers.

                                                    -Scott


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