postfix/mail: server blacklisted -- what have I done wrong?

[Lea Gris]

Matt Price a écrit :
> Hi folks,
> 
> On a very small server running postfix and apache under breezy, I seem
> to have gotten into some kind of trouble.  A mail sent this morning from
> the system was bounced back from gmx.de with the following message:
> 
> host mx0.gmx.net[213.165.64.100] said: 550-5.7.1 {mx016}
>     The IP address of the server you are using to connect to GMX is
> listed in
>     550-5.7.1 the Composite Blocking List (CBL). 550-5.7.1  550-5.7.1For
>     additional information, please visit 550-5.7.1
>     http://cbl.abuseat.org/lookup.cgi?ip=128.100.34.8  and 550 5.7.1 (
>     http://www.gmx.net/serverrules ) (in reply to RCPT TO command)
> 
> -----------------
> so, I followed the link, which ultimately led me to this page about HELO
> misconfiguration:
> http://cbl.abuseat.org/lh.html
> 
> Still wish I knew what "HELO" was about, but at least it helps.
> Turns out that I I had been having some trouble in the last few weeks
> with rejected mail complaining about "localhost.localdomain".  Finally
> fixed it a few days ago by editing /etc/postfix/main.cf 
> ----
> # myhostname = localhost.localdomain
> myhostname = a.legitimate.domain.name
> ----
> 
> so a couple of questions follow for me:
> 
> 1 - is this the likely cause of the problem?  THat is, have I already
> fixed a problem that has only just now arisen?
> 2 - If localhost.localdomain is ALWAYS a broken value for myaddress, how
> does it come about that this is even a configuration option?  SHould I
> for instance file a bug?

not a bug.

Either you have a dynamic IP address or an address listed as such in the
related RBLs.

Either the distination MX check for proper FQDN which can not be with
dynamic IP address from internet providers that may not have proper
reverse DNS either.

The right thing to do is configure a Postfix RelayHost to your Internet
Provider smtp relay such as smtp.myprovider.tld

sudo dpkg-reconfigure postfix and choose satellite system and provide
the smtp relay name.

or

edit
/etc/postfix/main.cf
relayhost = smtp.whateveryourispmailrelayis.tld


-- 
Léa Gris