[TriLUG] DNS Questions / Help
Lisa C. Boyd
leaseahb at gmail.com
Thu Mar 23 20:38:13 EST 2006
I have a client who is asking me to explain some warnings on a DNS
Report. Can ya'll give me some easy to understand advice as to what
these warning are or how to fix them?
--- Warning #1 ---
WARN TCP Allowed
WARNING: One or more of your DNS servers does not accept TCP
connections. Although rarely used, TCP connections are occasionally used
instead of UDP connections. When firewalls block the TCP DNS
connections, it can cause hard-to-diagnose problems. The problem servers
This site is hosted on a shared virtual web host (like most) so I'm
pretty sure we can ignore this warning because we have no control over
the name servers.
--- Warning #2 ---
WARN Mail server host name in greeting
WARNING: One or more of your mailservers is claiming 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 (and RFC2821
4.3.1). Note that the hostname given in the SMTP greeting should have an
A record pointing back to the same server.
I'm not sure we can do anything about this one either.
--- Warning #3 ---
WARN SPF record
Your domain does not have an SPF record. This means that spammers can
easily send out E-mail that looks like it came from your domain, which
can make your domain look bad (if the recipient thinks you really sent
it), and can cost you money (when people complain to you, rather than
the spammer). You may want to add an SPF record ASAP, as 01 Oct 2004 was
the target date for domains to have SPF records in place (Hotmail, for
example, started checking SPF records on 01 Oct 2004).
This one I have no clue.
Thanks for any feedback you can give me :) as always!
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