[plug] Mail domain error

[Nigel Duff]

 Hi all,

	I have just tried replying to an email, which was promptly
returned with the following error;

   ----- Transcript of session follows -----
... while talking to carmen.murdoch.edu.au.:
>>> MAIL From:<peregrin at caduceus.iinet.net.au> SIZE=944
<<< 501 <peregrin at caduceus.iinet.net.au>... Sender domain must exist
501 user at carmen.murdoch.edu.au... Data format error

 Doing a bit of a search on the net, I am not sure if this is a Sendmail
error or my client (mutt) error. I have configured sendmail with 

# who I masquerade as (null for no masquerading) (see also $=M)
DMiinet.net.au

Is there something else I should add to sendmail?

Thanks

Nigel