Date: Mon, 15 Oct 2001 11:53:48 -0400 From: "Drew J. Weaver" <drew.weaver@thenap.com> To: 'Brian' <bri@sonicboom.org> Cc: "'freebsd-net@freebsd.org'" <freebsd-net@freebsd.org> Subject: RE: DNS causing problems with sendmail? Message-ID: <B1A7D9973EBED3119ADD009027DC86492B16E2@MAILMAN>
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[-- Attachment #1 --] After 2 or 3 minutes it does work, the weird thing is that it was working No problem for 2 years and then suddenly it stopped working. Yes, our modem pool IP addresses all have PTR records, just not forward DNS (we aren't that stupid). When I specify a few of the non working hosts in /etc/hosts it works fine then. One of the IP addresses in question is 206.222.10.7, if you do a host 206.222.10.7 it does reverse. So I guess my question is, what the dilly-o? -----Original Message----- From: Brian [mailto:bri@sonicboom.org] Sent: Monday, October 15, 2001 11:30 AM To: Drew J. Weaver; 'freebsd-net@freebsd.org' Subject: Re: DNS causing problems with sendmail? After the 2 or 3 minute delay, does it work? Looked in /var/log/maillog for reject causes? Are all the hosts you want to allow to send specified in /etc/mail/relay-domains? If you want to try to see if dns is the cause, specify a few of the non working hosts in /etc/hosts. Personally as an isp customer, if forward and reverse dns is not setup, I'd be looking for a new isp. Some sites will not allow you to connect in this situation. TCP wrappers often includes this entry. # Prevent those with no reverse DNS from connecting. ALL : PARANOID : RFC931 20 : deny Bri ----- Original Message ----- From: Drew J. <mailto:drew.weaver@thenap.com> Weaver To: 'freebsd-net@freebsd.org' <mailto:'freebsd-net@freebsd.org'> Sent: Monday, October 15, 2001 5:40 AM Subject: DNS causing problems with sendmail? Hi, I've had this problem for a few days now, we have a small dial-up ISP and when users dial into one of our cities they get a 209.xxx.xxx.xxx IP and our mail server responds normally, we have another modem pool in that city that consists of 206.xxx.xxx.xxx IP addresses, if a user gets a 206.xxx.xxx.xxx IP address and they attempt to check mail it takes a good 2-3 minutes before the sendmail connection starts, which is an obvious problem because of the timeouts on email clients (and.. 2-3 minutes is just bad). I've been kinda asking around on comp.mail.sendmail about this issue and they are telling me it is a DNS problem. Well, I know that my mail server can reverse the IP addresses because if I am logged in and issue a host command with the IP after it the server is able to produce the proper reverse name. Another user thought it was because I have no Forward dns (a record) for what the IPs are reversed to, but the fact is I've NEVER had any A records or anything for my modem pools. I also have another server running the same version of sendmail, and if I dial into this city and get a 206.xxx.xxx.xxx IP and telnet to port 25 on that server it comes up instantly. So this appears to be an issue only effecting one daemon on one server. The afflicted server also runs a POP daemon that isn't having any problems of this type. Does anyone have a clue on this? I'm awfully confused at this point. Thanks, -Drew [-- Attachment #2 --] <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:st1="urn:schemas-microsoft-com:office:smarttags" xmlns="http://www.w3.org/TR/REC-html40">; <head> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii"> <meta name=ProgId content=Word.Document> <meta name=Generator content="Microsoft Word 10"> <meta name=Originator content="Microsoft Word 10"> <link rel=File-List href="cid:filelist.xml@01C1556F.770BD700"> <o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="time"/> <o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="date"/> <!--[if gte mso 9]><xml> <o:OfficeDocumentSettings> <o:DoNotRelyOnCSS/> </o:OfficeDocumentSettings> </xml><![endif]--><!--[if gte mso 9]><xml> <w:WordDocument> <w:SpellingState>Clean</w:SpellingState> <w:GrammarState>Clean</w:GrammarState> <w:DocumentKind>DocumentEmail</w:DocumentKind> <w:EnvelopeVis/> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if !mso]> <style> st1\:*{behavior:url(#default#ieooui) } </style> <![endif]--> <style> <!-- /* Font Definitions */ @font-face {font-family:Tahoma; panose-1:2 11 6 4 3 5 4 4 2 4; mso-font-charset:0; mso-generic-font-family:swiss; mso-font-pitch:variable; mso-font-signature:553679495 -2147483648 8 0 66047 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} a:link, span.MsoHyperlink {color:blue; text-decoration:underline; text-underline:single;} a:visited, span.MsoHyperlinkFollowed {color:purple; text-decoration:underline; text-underline:single;} span.EmailStyle17 {mso-style-type:personal; mso-style-noshow:yes; mso-ansi-font-size:10.0pt; mso-bidi-font-size:10.0pt; font-family:Arial; mso-ascii-font-family:Arial; mso-hansi-font-family:Arial; mso-bidi-font-family:Arial; color:windowtext;} span.EmailStyle18 {mso-style-type:personal-reply; mso-style-noshow:yes; mso-ansi-font-size:10.0pt; mso-bidi-font-size:10.0pt; font-family:Arial; mso-ascii-font-family:Arial; mso-hansi-font-family:Arial; mso-bidi-font-family:Arial; color:navy;} @page Section1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.Section1 {page:Section1;} --> </style> <!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman";} </style> <![endif]--><!--[if gte mso 9]><xml> <o:shapedefaults v:ext="edit" spidmax="1026" /> </xml><![endif]--><!--[if gte mso 9]><xml> <o:shapelayout v:ext="edit"> <o:idmap v:ext="edit" data="1" /> </o:shapelayout></xml><![endif]--> </head> <body bgcolor=white lang=EN-US link=blue vlink=purple style='tab-interval:.5in'> <div class=Section1> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'>After 2 or 3 minutes it does work, the weird thing is that it was working No problem for 2 years and then suddenly it stopped working. Yes, our modem pool IP addresses all have PTR records, just not forward DNS (we aren't that stupid). When I specify a few of the non working hosts in /etc/hosts it works fine then. One of the IP addresses in question is 206.222.10.7, if you do a host 206.222.10.7 it does reverse. So I guess my question is, what the dilly-o?<o:p></o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p> <p class=MsoNormal style='margin-left:.5in'><font size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>-----Original Message-----<br> <b><span style='font-weight:bold'>From:</span></b> Brian [mailto:bri@sonicboom.org] <br> <b><span style='font-weight:bold'>Sent:</span></b> </span></font><st1:date Month="10" Day="15" Year="2001"><font size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>Monday, October 15, 2001</span></font></st1:date><font size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> </span></font><st1:time Hour="11" Minute="30"><font size=2 face=Tahoma><span style='font-size:10.0pt; font-family:Tahoma'>11:30 AM</span></font></st1:time><font size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'><br> <b><span style='font-weight:bold'>To:</span></b> Drew J. Weaver; 'freebsd-net@freebsd.org'<br> <b><span style='font-weight:bold'>Subject:</span></b> Re: DNS causing problems with sendmail?</span></font></p> <p class=MsoNormal style='margin-left:.5in'><font size=3 face="Times New Roman"><span style='font-size:12.0pt'><o:p> </o:p></span></font></p> <div> <p class=MsoNormal style='margin-left:.5in'><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'>After the 2 or 3 minute delay, does it work? Looked in /var/log/maillog for reject causes? Are all the hosts you want to allow to send specified in /etc/mail/relay-domains? If you want to try to see if dns is the cause, specify a few of the non working hosts in /etc/hosts. Personally as an isp customer, if forward and reverse dns is not setup, I'd be looking for a new isp. Some sites will not allow you to connect in this situation. TCP wrappers often includes this entry.</span></font><o:p></o:p></p> </div> <div> <p class=MsoNormal style='margin-left:.5in'><font size=3 face="Times New Roman"><span style='font-size:12.0pt'> <o:p></o:p></span></font></p> </div> <div> <p class=MsoNormal style='margin-left:.5in'><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'># Prevent those with no reverse DNS from connecting.<br> ALL : PARANOID : RFC931 20 : deny</span></font><o:p></o:p></p> </div> <div> <p class=MsoNormal style='margin-left:.5in'><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'>Bri<o:p></o:p></span></font></p> </div> <blockquote style='border:none;border-left:solid black 1.5pt;padding:0in 0in 0in 4.0pt; margin-left:3.75pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'> <div> <p class=MsoNormal style='margin-left:.5in'><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'>----- Original Message ----- <o:p></o:p></span></font></p> </div> <div style='font-color:black'> <p class=MsoNormal style='margin-left:.5in;background:#E4E4E4'><b><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial;font-weight:bold'>From:</span></font></b><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> <a href="mailto:drew.weaver@thenap.com" title="drew.weaver@thenap.com">Drew J. Weaver</a> <o:p></o:p></span></font></p> </div> <div> <p class=MsoNormal style='margin-left:.5in'><b><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial;font-weight:bold'>To:</span></font></b><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> <a href="mailto:'freebsd-net@freebsd.org'" title="freebsd-net@FreeBSD.ORG">'freebsd-net@freebsd.org'</a> <o:p></o:p></span></font></p> </div> <div> <p class=MsoNormal style='margin-left:.5in'><b><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial;font-weight:bold'>Sent:</span></font></b><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> </span></font><st1:date Month="10" Day="15" Year="2001"><font size=2 face=Arial><span style='font-size: 10.0pt;font-family:Arial'>Monday, October 15, 2001</span></font></st1:date><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> </span></font><st1:time Hour="5" Minute="40"><font size=2 face=Arial><span style='font-size:10.0pt; font-family:Arial'>5:40 AM</span></font></st1:time><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'><o:p></o:p></span></font></p> </div> <div> <p class=MsoNormal style='margin-left:.5in'><b><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial;font-weight:bold'>Subject:</span></font></b><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> DNS causing problems with sendmail?<o:p></o:p></span></font></p> </div> <div> <p class=MsoNormal style='margin-left:.5in'><font size=3 face="Times New Roman"><span style='font-size:12.0pt'><o:p> </o:p></span></font></p> </div> <p class=MsoNormal style='margin-left:.5in;text-indent:.5in'><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'>Hi, I've had this problem for a few days now, we have a small dial-up ISP and when users dial into one of our cities they get a 209.xxx.xxx.xxx IP and our mail server responds normally, we have another modem pool in that city that consists of 206.xxx.xxx.xxx IP addresses, if a user gets a 206.xxx.xxx.xxx IP address and they attempt to check mail it takes a good 2-3 minutes before the sendmail connection starts, which is an obvious problem because of the timeouts on email clients (and.. 2-3 minutes is just bad). I've been kinda asking around on comp.mail.sendmail about this issue and they are telling me it is a DNS problem. Well, I know that my mail server can reverse the IP addresses because if I am logged in and issue a host command with the IP after it the server is able to produce the proper reverse name. Another user thought it was because I have no Forward dns (a record) for what the IPs are reversed to, but the fact is I've NEVER had any A records or anything for my modem pools. I also have another server running the same version of sendmail, and if I dial into this city and get a 206.xxx.xxx.xxx IP and telnet to port 25 on that server it comes up instantly. So this appears to be an issue only effecting one daemon on one server. The afflicted server also runs a POP daemon that isn't having any problems of this type.<o:p></o:p></span></font></p> <p class=MsoNormal style='margin-left:.5in;text-indent:.5in'><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'><o:p> </o:p></span></font></p> <p class=MsoNormal style='margin-left:.5in;text-indent:.5in'><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'>Does anyone have a clue on this? I'm awfully confused at this point.<o:p></o:p></span></font></p> <p class=MsoNormal style='margin-left:.5in;text-indent:.5in'><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'><o:p> </o:p></span></font></p> <p class=MsoNormal style='margin-left:.5in;text-indent:.5in'><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'>Thanks,<o:p></o:p></span></font></p> <p class=MsoNormal style='margin-left:.5in;text-indent:.5in'><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'>-Drew<o:p></o:p></span></font></p> <p class=MsoNormal style='margin-left:.5in;text-indent:.5in'><font size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'><o:p> </o:p></span></font></p> </blockquote> </div> </body> </html>
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