The mutt mail program was misconfigured on shell and shellx resulting in mail being sent from those machines using mutt having from addresses of user@shell.eskimo.com and user@shellx.eskimo.com respectively.

This in turn caused people replying to e-mail from those incorrect addresses to have their e-mail bounced.

Not all customers experienced this problem as many who were more familiar with mutt simply added set domain=eskimo.com to their .muttrc files.

I have now added this to the system wide /etc/Muttrc file so it will now generate e-mail with correct From addresses.