> 31. ADDRESS REWRITING
>
> One situation in which Exim does not automatically rewrite a domain is when it
> is the name of a CNAME record in the DNS. The older RFCs suggest that such a
> domain should be rewritten using the "canonical" name, and some MTAs do this.
> The new RFCs do not contain this suggestion.
I can't find a newer SMTP RFC than 2821...
RFC2821 Section 5:
> If a CNAME record is found instead, the resulting name is processed as if it were the initial name.
I think this is too vague considering it's in the "Address Resolution" section, it can either mean replacing the sender domain or simply following a CNAME.
While exim claims not to do rewriting automatically, it does:
wind.lp0.eu. 3600 IN CNAME blackhole.arlott.org.uk.
blackhole.arlott.org.uk. 86400 IN AAAA 2001:4bd0:1000:0:240:f4ff:fe30:2ab8
blackhole.arlott.org.uk. 86400 IN A 84.92.75.21
# exim -d -bt postmaster@???
Address testing: uid=0 gid=12 euid=0 egid=12
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Testing postmaster@???
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Considering postmaster@???
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
routing postmaster@???
--------> dnslookup router <--------
local_part=postmaster domain=wind.lp0.eu
checking domains
cached no match for +local_domains
cached lookup data = NULL
wind.lp0.eu in "! +local_domains"? yes (end of list)
calling dnslookup router
dnslookup router called for postmaster@???
domain = wind.lp0.eu
DNS lookup of wind.lp0.eu (MX) succeeded
DNS lookup of blackhole.arlott.org.uk (MX) gave NO_DATA
returning DNS_NODATA
DNS lookup of wind.lp0.eu (AAAA) succeeded
2001:4bd0:1000:0:240:f4ff:fe30:2ab8 in "0.0.0.0 : 127.0.0.0/8"? no (end of list)
DNS lookup of blackhole.arlott.org.uk (A) succeeded
84.92.75.21 in "0.0.0.0 : 127.0.0.0/8"? no (end of list)
local host found for non-MX address
fully qualified name = blackhole.arlott.org.uk
blackhole.arlott.org.uk 2001:4bd0:1000:0:240:f4ff:fe30:2ab8 mx=-1 sort=-991
blackhole.arlott.org.uk 84.92.75.21 mx=-1 sort=-153
domain changed to blackhole.arlott.org.uk
rewriting header lines
re-routed to postmaster@???
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Considering postmaster@???
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
routing postmaster@???
--
Simon Arlott
