Re: [swinog] PTR records with CNAME ?
On 2018-05-30 17:35, Per Jessen wrote: > Jeroen Massar wrote: > >> On 2018-05-30 16:44, Per Jessen wrote: >>> According to RFC1034 and 2181, a PTR record using a CNAME is not >>> permitted. I believe this to still be correct, postfix certainly >>> doesn't work with a CNAME when it does a reverse lookup. >> >> Postfix certainly does as: >> >> $ dig +short 50.131.144.213.in-addr.arpa. ptr >> 50.63-28.131.144.213.in-addr.arpa. >> citadel.ch.unfix.org. >> >> would otherwise not work and that trick of CNAME'ing in-addr.arpa >> space is used a lot by ISPs to delegate space (as per the above >> example where init7 forwards them to my nameservers). >> >> There is also a nice RFC on that: >> https://www.ietf.org/rfc/rfc2317.txt > > Okay, thanks for clarifying that - I was wondering. I don't why my > postfixes come up with host name 'unknown'. Where does postfix say 'unknown'? In the prepended "Received: from ..." header? in logs? Can be many reasons why it does not trust the originally provided data, especially as HELO/EHLO can be spoofed. Also depends on the resolver etc etc, many factors ;) Greets, Jeroen ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
Re: [swinog] PTR records with CNAME ?
Jeroen Massar wrote: > On 2018-05-30 16:44, Per Jessen wrote: >> According to RFC1034 and 2181, a PTR record using a CNAME is not >> permitted. I believe this to still be correct, postfix certainly >> doesn't work with a CNAME when it does a reverse lookup. > > Postfix certainly does as: > > $ dig +short 50.131.144.213.in-addr.arpa. ptr > 50.63-28.131.144.213.in-addr.arpa. > citadel.ch.unfix.org. > > would otherwise not work and that trick of CNAME'ing in-addr.arpa > space is used a lot by ISPs to delegate space (as per the above > example where init7 forwards them to my nameservers). > > There is also a nice RFC on that: > https://www.ietf.org/rfc/rfc2317.txt Okay, thanks for clarifying that - I was wondering. I don't why my postfixes come up with host name 'unknown'. -- Per Jessen, Zürich (28.8°C) http://www.dns24.ch/ - your free DNS host, made in Switzerland. ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
Re: [swinog] PTR records with CNAME ?
On 2018-05-30 16:44, Per Jessen wrote: > According to RFC1034 and 2181, a PTR record using a CNAME is not > permitted. I believe this to still be correct, postfix certainly > doesn't work with a CNAME when it does a reverse lookup. Postfix certainly does as: $ dig +short 50.131.144.213.in-addr.arpa. ptr 50.63-28.131.144.213.in-addr.arpa. citadel.ch.unfix.org. would otherwise not work and that trick of CNAME'ing in-addr.arpa space is used a lot by ISPs to delegate space (as per the above example where init7 forwards them to my nameservers). There is also a nice RFC on that: https://www.ietf.org/rfc/rfc2317.txt Greets, Jeroen ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
[swinog] PTR records with CNAME ?
According to RFC1034 and 2181, a PTR record using a CNAME is not permitted. I believe this to still be correct, postfix certainly doesn't work with a CNAME when it does a reverse lookup. Any comments? thanks. Per -- Per Jessen, Zürich (28.6°C) http://www.dns24.ch/ - free dynamic DNS, made in Switzerland. ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
