Re: [swinog] Has Bluewin a DNS Problem
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?) [EMAIL PROTECTED]... 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 ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
Re: [swinog] Has Bluewin a DNS Problem
Hi, Bluewin does a reverse DNS lookup on your IP (195.141.232.78), ..yes Bluewin does a normal forward DNS lookup, using the result from the above query. we don't. The resolver implementation of our MTA software appears to have a problem with truncated UDP responses. (Btw: Why do you have such a lenghty PTR record for 195.141.232.78 ?) I'm about to implement a workaround for this issue. Regards, Adrian ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
Re: [swinog] Has Bluewin a DNS Problem
Franco Hug wrote: 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. plus another 20 hosts This is a silly reverse setup. A reverse lookup should only return one hostname, not 20. /Per Jessen, Herrliberg ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
RE: [swinog] Has Bluewin a DNS Problem
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. plus another 20 hosts This is a silly reverse setup. A reverse lookup should only return one hostname, not 20. /Per Jessen, Herrliberg Yes, I agree. This is really a bad design and has nothing to do with DNS problems on the bluewin side, even if the bluewin DNS might have troubles resolving truncated requests, IMHO. Cheers, Florian ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
Re: [swinog] Has Bluewin a DNS Problem
The Problem is we have on this IP 30 Domains... When I must have for everery Domain an IP for the reverse of Bluewin is a big Problem... I must have in future an A Net... I think Bluewin must fix this. Greetings X. Aerni - Original Message - From: Franco Hug [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Wednesday, March 26, 2008 1:29 PM Subject: Re: [swinog] Has Bluewin a DNS Problem 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?) [EMAIL PROTECTED]... 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 ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog ___ swinog mailing list swinog@lists.swinog.ch
Re: [swinog] Has Bluewin a DNS Problem
you can just take another name for the mailserver of these domains - only one for all so you have one PTR Record, pointing to mailserver.domain then you can use the same domainname for mailserver on the others 29 Domains. this fixes this problem Silvan Am 26.03.2008 um 13:45 schrieb Xaver Aerni: The Problem is we have on this IP 30 Domains... When I must have for everery Domain an IP for the reverse of Bluewin is a big Problem... I must have in future an A Net... I think Bluewin must fix this. Greetings X. Aerni ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
RE: [swinog] Has Bluewin a DNS Problem
... This is a silly reverse setup. A reverse lookup should only return one hostname, not 20. ... Well, tend to agree. What about the most stupid wanabe Spam-fighter which are very unhappy as in place (e.g. the third-party service provider systems acting with some SC subsidiaries...) which high rate valid messages if certain brain-dead conditions like PTR not matching MX don't match? If this approach works out, it could be considered. It is not illegal. It's just against what we are used to over the last 20+ years. Just like the A records on second level domain names - depreciated some years ago, tough more and more common. Under the line, it is likely not a DNS issue, but the inability by some mail or AS systems resolving lists. Suspect my servers will fail, too. Xaver, pls send private reply for a test from that system, anytime. Regards, -Kurt. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Per Jessen Sent: Wednesday, March 26, 2008 2:26 PM To: swinog@lists.swinog.ch Subject: Re: [swinog] Has Bluewin a DNS Problem ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
Re: [swinog] Has Bluewin a DNS Problem
Hi Kurt, On 26.03.2008, at 15:03, Kurt A. Schumacher wrote: ... This is a silly reverse setup. A reverse lookup should only return one hostname, not 20. ... What about the most stupid wanabe Spam-fighter which are very unhappy as in place (e.g. the third-party service provider systems acting with some SC subsidiaries...) which high rate valid messages if certain brain-dead conditions like PTR not matching MX don't match? There are a lot of E-Mail Providers (i.e. gmx) behaving like this already. If A, PTR, MX and HELO are not exactly the same (all four) the message is marked as SPAM. There are pro's and cons for this... I would not rate E-Mails solely because of those four points, but that's only me CU Tobias ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
RE: [swinog] Has Bluewin a DNS Problem
Kurt A. Schumacher wrote: ... This is a silly reverse setup. A reverse lookup should only return one hostname, not 20. ... Well, tend to agree. What about the most stupid wanabe Spam-fighter which are very unhappy as in place (e.g. the third-party service provider systems acting with some SC subsidiaries...) which high rate valid messages if certain brain-dead conditions like PTR not matching MX don't match? Trying to work around them with a dodgy DNS setup is not the right course of action, IMHO. If this approach works out, it could be considered. It is not illegal. Correct - it's just silly and it doesn't work as expected. 1) a properly working resolver library will return multiple records rotated once for every lookup, so you're never guaranteed to get the same answer to a reverse lookup. 2) most applications, e.g. mail-servers, that do reverse lookups do not expect more than one reply, and will always only process the first one. It's just against what we are used to over the last 20+ years. Plus it doesn't work. /Per Jessen, Herrliberg -- http://www.spamchek.com/ - your spam is our business. ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
Re: [swinog] Has Bluewin a DNS Problem
On the Wed, Mar 26, 2008 at 01:57:46PM +0100, Adrian Ulrich blubbered: Hoi. The resolver implementation of our MTA software appears to have a problem with truncated UDP responses. (Btw: Why do you have such a lenghty PTR record for 195.141.232.78 ?) I may be wrong, but doesn't DNS use TCP if the answer to a query exceeds a certain length? CU, Venty -- Wo Informationen fehlen, da entstehen Geruechte. ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
Re: [swinog] Has Bluewin a DNS Problem
On the Wed, Mar 26, 2008 at 02:42:36PM +0100, Tonnerre Lombard blubbered: Hoi. 1. it is highly unlikely that these stupid wannabe SPAM filters get the response containing so many PTR records right. It is most likely that either the software blows up or that it only ever considers the entry it receives first. Most mailservers just check if there is a PTR record at all and if there is none, reject the mail with a 5xx DSN. (Most likely the software blowing up will not even be remarked but instead the mail will be rejected silently.) Clever spamfilters will just add another score point to the spam score and not just pass or discard a mail based on a single criteria. Under the line, it is likely not a DNS issue, but the inability by some mail or AS systems resolving lists. Suspect my servers will fail, too. Xaver, pls send private reply for a test from that system, anytime. It is also a DNS issue, depending on the number of results returned; the size of a DNS/UDP response is limited to 1 UDP packet, which again is limited in size. Not everyone uses DNS over TCP, and it is unlikely to be adapted just because of such a stupid and useless SPAM filtering measure. While Xari's Setup with tons of PTR records is plain stupid. Xari, you should have a read about MX records. =:-) But DNS uses UDP and TCP as I just checked. RFC 1035, Chapter 4.2 says: The Internet supports name server access using TCP [RFC-793] on server port 53 (decimal) as well as datagram access using UDP [RFC-768] on UDP port 53 (decimal). CU, Venty -- Wo Informationen fehlen, da entstehen Geruechte. ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
