Domain name problem with SMTP

[Anders Pettersson <anders.pettersson@avitec.se>]

I am having some difficulty in the SMTP envelope when sending
mail. The local DNS assign a local domain name to the computer, and
when I am sending mail through an outside SMTP server it refuses to
relay the mail because an A or MX record is missing in public DNSes.

I have tried to correct this by setting the variables as below

(setq
       smtpmail-local-domain "valid.domain"
       gnus-local-domain "valid.domain"
)

But it does not seem to work. When Gnus talks to the SMTP server i get
this result: (fromt the SMTP trace buffer)

MAIL FROM: <ichi@INVALID.domain> SIZE=713
451 <ichi@INVALID.domain>...Invalid domain, no MX nor A record found

(The actual domain names has been changed to protect the innocent :)

I am running "Gnus/5.9.0" in GNU "Emacs/21.2.1".

I did a M-x apropos and tried to find anything else suitable, but
could not find it. I could perhaps change the name of the localhost to
a valid DNS name, but it would not be right since it would mismatch
with the local DNS server.

Any help appreciated.