exim question

Vernon Schryver vjs@calcite.rhyolite.com
Tue Jul 13 17:20:22 UTC 2010

I have question about exim.

seems to imply that exim violates the SMTP standards by generating
address literals in Received: headers without the required
"IPv6:" tag.   That NANOG thread seems to say that exim generates

    Received: from s0.nanog.org (s0.nanog.org [2001:48a8:6880:95::20]) ...

instead of

    Received: from s0.nanog.org (s0.nanog.org [IPv6:2001:48a8:6880:95::20]) ...

Is that true?

I care because the DCC client programs, dccifd, dccm, and dccproc
try to parse Received headers for the IP address of the SMTP client
or mail sending system.  Some DCC installations use dccifd with exim.

Should I modify the DCC client programs to recognize IPv6 address
literals without the "IPv6;" tag?  It would cost some CPU cycles.
It might be a little dodgy, because except for colons, IPv6 addresses
can look like host names.

dccifd needs the IP address of the SMTP client for whitelisting
among other things.

Vernon Schryver    vjs@rhyolite.com

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