rejected mail DNS unresolved

["Luke (Terry) Vanderfluit" <luke@xxxxxxxxxxxxxxx>]

Hi,

I'm trying to send to this server here:
but because I'm sending from a dialup box, the server can't resolve my
domain name. 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   ----- Transcript of session follows -----
... while talking to mx0.gmx.de.:
>>> MAIL From:<luke@xxxxxxxxxxxxxxxxxxx>
<<< 550 5.1.8 {mx055} Cannot resolve your domain
554 5.0.0 Service unavailable
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


I've suppressed the from field in .muttrc with 'unset use_from'
and added a 'my_hdr From: luke@xxxxxxxxxxxxxxx'
but somehow the server still doesn't want to receive my mail.
I've tried sending from some webmail addresses to myself to inspect the
headers and not really found an answer,

How would I suppress that info? Obviously the server admin at gmx.de
have a security measure in place that they don't want to change.

what d'ya think?

thanks,
Luke


-- 
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Luke (Terry) Vanderfluit 
Mobile: 0421 276 282     
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