Hi Xaver,
I had a similar problem when I set up the mail server on my virtual server and wanted to send mail to domains that are hosted by zoneedit.com.
After searching a while, I think this is the way how it works:
Step 1: ====== Bluewin does a reverse DNS lookup on your IP (195.141.232.78), which returns the following:
# nslookup
195.141.232.78
;; Truncated, retrying in TCP mode. Server: www.multipop.ch. Address: 195.141.232.253#53
78.232.141.195.in-addr.arpa name = mailhost.aa795.ch. 78.232.141.195.in-addr.arpa name = mailhost.aerni.net. 78.232.141.195.in-addr.arpa name = mailhost.bar16.ch. 78.232.141.195.in-addr.arpa name = mailhost.sysop.ch. 78.232.141.195.in-addr.arpa name = mailhost.zingg.org. 78.232.141.195.in-addr.arpa name = mailhost.satshop.cc. 78.232.141.195.in-addr.arpa name = mailhost.aquacare.ch. 78.232.141.195.in-addr.arpa name = mailhost.glaettli.cc. 78.232.141.195.in-addr.arpa name = mailhost.multipop.ch. 78.232.141.195.in-addr.arpa name = mailhost.satshops.ch. 78.232.141.195.in-addr.arpa name = mailhost.spacebbs.ch. 78.232.141.195.in-addr.arpa name = mailhost.amigaland.ch. 78.232.141.195.in-addr.arpa name = mailhost.augsauger.ch. 78.232.141.195.in-addr.arpa name = mailhost.begegnung.ch. 78.232.141.195.in-addr.arpa name = mailhost.satvision.ch. 78.232.141.195.in-addr.arpa name = mailhost.hackernews.ch.ch. 78.232.141.195.in-addr.arpa name = mailhost.natel-news.ch. 78.232.141.195.in-addr.arpa name = mailhost.satanlagen.ch. 78.232.141.195.in-addr.arpa name = mailhost.satantennen.ch. 78.232.141.195.in-addr.arpa name = mailhost.wiso-schoch.ch. 78.232.141.195.in-addr.arpa name = mailhost.xariffusion.ch. 78.232.141.195.in-addr.arpa name = mailhost.sat-receiver.ch. 78.232.141.195.in-addr.arpa name = mailhost.estherundpetr.ch. 78.232.141.195.in-addr.arpa name = mailhost.luisenstrasse.ch. 78.232.141.195.in-addr.arpa name = mailhost.arthurandersen.ch. 78.232.141.195.in-addr.arpa name = mailhost.elektronik-news.ch. 78.232.141.195.in-addr.arpa name = mailhost.zuerichsee-gastro.ch. 78.232.141.195.in-addr.arpa name = mailhost.pop.ch. 78.232.141.195.in-addr.arpa name = mailhost.rtv.ch. 78.232.141.195.in-addr.arpa name = mailhost.dsng.ch.
Step 2: ====== Bluewin does a "normal" forward DNS lookup, using the result from the above query. The forward (A) query has to match your IP address, otherwise Bluewin will complain about the PTR record.
However, the above query returned more than one value, so I am not sure which host is used for the lookup - I guess that just the first host is taken. Since the order is random, you cannot say anything reliable about which host will be used for the lookup. Maybe it even fails directly if the response is not unique - I don't know.
When I tried the lookup the first time, mailhost.aquacare.ch was used for the query. However, mailhost.aquacare.ch does not exist (even the domain does not exist), so the lookup fails and rightly so Bluewin complains about your PTR record.
I think the purpose of this reverse and forward DNS lookup procedure is to prevent spam, since most spam comes from hacked machines (mostly from dynamic IP address ranges) which do not have correct PTR records - just as it is the case with your machine ;-)
Gruass, Franco
Adrian Ulrich wrote:
Good Morning,
Is your source ip 195.141.232.78 ?
Regards, Adrian
swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
Xaver Aerni wrote:
Our System receive ex. This MSG
The original message was received at Tue, 25 Mar 2008 16:20:47 +0100 from localhost [127.0.0.1]
----- Transcript of session follows ----- ... while talking to mxbw.bluewin.ch.: <<< 451 No thanks. (How about PTR records?) ... while talking to mxzhh.bluewin.ch.:
QUIT
<<< 451 No thanks. (How about PTR records?) ... while talking to mxzhb.bluewin.ch.:
QUIT
<<< 451 No thanks. (How about PTR records?) niesen18@bluewin.ch... Deferred: 451 No thanks. (How about PTR records?) Warning: message still undelivered after 4 hours Will keep trying until message is 5 days old
Xaver Aerni Zürichstrasse 10a 8340 Hinwil Tel. 001 707 361 68 39