[Mailman-Users] Problems with To Header

Joseph Perrie jperrie at us.ibm.com
Sat Jun 10 01:48:46 CEST 2006

All of the emails sent by our server out to the mailing lists were using
the host name instead of the DNS A record for the Mailman VirtualHost. I
tried for days to fix this and eventually got the feeling that it was DNS
related. However, I still couldn't see why Sendmail would force the
To-header back to the canonical name when Mailman was setting it correctly.
Eventually, I happened across this email (
 on the dev list that solved the problem by manually editting sendmail.cf's
rulesets to bypass canonicalization. I'm sure this violates some RFC.
Although, the hack does indeed solve the problem. The actual wizardry was
to comment out the following line in sendmail.cf.

# pass to name server to make hostname canonical
# R$* $| $* < @ $* > $*         $: $2 < @ $[ $3 $] > $4

It's absolutely wrong to do this because if you edit sendmail.mc, and
restart sendmail, the cf file gets regenerated automatically which
obliterates the change. Is there a better way to fix this without violating
RFCs and changing sendmail rulesets? Note: I don't have access to the DNS

Tony Perrie
Engineer, STI Convergence Team, BQQA
11501 Burnet Rd, Building 906/3007C Austin, TX, 78759
Phone: 512-838-1402, T/L: 678-1402
Fax: 512-838-2132

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