Date: Mon, 15 Oct 2001 08:30:18 -0700 From: "Brian" <bri@sonicboom.org> To: "Drew J. Weaver" <drew.weaver@thenap.com>, "'freebsd-net@freebsd.org'" <freebsd-net@FreeBSD.ORG> Subject: Re: DNS causing problems with sendmail? Message-ID: <007701c1558e$585a1460$3324200a@sonicboom.org> References: <B1A7D9973EBED3119ADD009027DC86492B16CF@MAILMAN>
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This is a multi-part message in MIME format. ------=_NextPart_000_0070_01C15553.9F600080 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable 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 -----=20 From: Drew J. Weaver=20 To: 'freebsd-net@freebsd.org'=20 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. =20 Does anyone have a clue on this? I'm awfully confused at this point. =20 Thanks, -Drew =20 ------=_NextPart_000_0070_01C15553.9F600080 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML xmlns=3D"http://www.w3.org/TR/REC-html40" xmlns:o =3D=20 "urn:schemas-microsoft-com:office:office" xmlns:w =3D=20 "urn:schemas-microsoft-com:office:word"><HEAD> <META http-equiv=3DContent-Type content=3D"text/html; = charset=3Diso-8859-1"> <META content=3DWord.Document name=3DProgId> <META content=3D"MSHTML 5.50.4807.2300" name=3DGENERATOR> <META content=3D"Microsoft Word 10" name=3DOriginator><LINK=20 href=3D"cid:filelist.xml@01C15554.7FB310A0" rel=3DFile-List><!--[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]--> <STYLE>@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; } P.MsoNormal { FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman"; = mso-style-parent: ""; mso-pagination: widow-orphan; = mso-fareast-font-family: "Times New Roman" } LI.MsoNormal { FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman"; = mso-style-parent: ""; mso-pagination: widow-orphan; = mso-fareast-font-family: "Times New Roman" } DIV.MsoNormal { FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman"; = mso-style-parent: ""; mso-pagination: widow-orphan; = mso-fareast-font-family: "Times New Roman" } A:link { COLOR: blue; TEXT-DECORATION: underline; text-underline: single } SPAN.MsoHyperlink { COLOR: blue; TEXT-DECORATION: underline; text-underline: single } A:visited { COLOR: purple; TEXT-DECORATION: underline; text-underline: single } SPAN.MsoHyperlinkFollowed { COLOR: purple; TEXT-DECORATION: underline; text-underline: single } SPAN.EmailStyle17 { COLOR: windowtext; FONT-FAMILY: Arial; mso-style-type: = personal-compose; mso-style-noshow: yes; mso-ansi-font-size: 10.0pt; = mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Arial; = mso-hansi-font-family: Arial; mso-bidi-font-family: Arial } SPAN.SpellE { mso-style-name: ""; mso-spl-e: yes } SPAN.GramE { mso-style-name: ""; mso-gram-e: yes } DIV.Section1 { page: Section1 } </STYLE> <!--[if gte mso 10]> <style> /* Style Definitions */=20 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]--></HEAD> <BODY lang=3DEN-US style=3D"tab-interval: .5in" vLink=3Dpurple = link=3Dblue=20 bgColor=3D#ffffff> <DIV><FONT face=3DArial size=3D2>After the 2 or 3 minute delay, does it = work? =20 Looked in /var/log/maillog for reject causes? Are all the hosts = you want=20 to allow to send specified in /etc/mail/relay-domains? If you want = to try=20 to see if dns is the cause, specify a few of the non working hosts in=20 /etc/hosts. Personally as an isp customer, if forward and reverse = dns is=20 not setup, I'd be looking for a new isp. Some sites will not allow = you to=20 connect in this situation. TCP wrappers often includes this=20 entry.</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2># Prevent those with no reverse DNS = from=20 connecting.<BR>ALL : PARANOID : RFC931 20 : deny<BR></FONT></DIV> <DIV><FONT face=3DArial size=3D2>Bri</DIV></FONT> <BLOCKQUOTE dir=3Dltr=20 style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; = BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV> <DIV=20 style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: = black"><B>From:</B>=20 <A title=3Ddrew.weaver@thenap.com = href=3D"mailto:drew.weaver@thenap.com">Drew J.=20 Weaver</A> </DIV> <DIV style=3D"FONT: 10pt arial"><B>To:</B> <A = title=3Dfreebsd-net@FreeBSD.ORG=20 = href=3D"mailto:'freebsd-net@freebsd.org'">'freebsd-net@freebsd.org'</A> = </DIV> <DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Monday, October 15, 2001 = 5:40=20 AM</DIV> <DIV style=3D"FONT: 10pt arial"><B>Subject:</B> DNS causing problems = with=20 sendmail?</DIV> <DIV><BR></DIV> <DIV class=3DSection1> <P class=3DMsoNormal style=3D"TEXT-INDENT: 0.5in"><FONT face=3DArial = size=3D2><SPAN=20 style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Hi, I've had this = problem for a=20 few days now, we have a small dial-up ISP and when users dial into one = of our=20 cities they get a 209.xxx.xxx.xxx IP and our mail server responds = normally, we=20 have another modem pool in that city that consists of 206.xxx.xxx.xxx = IP=20 addresses, if a user gets a 206.xxx.xxx.xxx IP address and they = attempt to=20 check mail it takes a good 2-3 minutes before the <SPAN=20 class=3DSpellE>sendmail</SPAN> connection starts, which is an obvious = problem=20 because of the timeouts on email clients (and.. 2-3 minutes is just = bad). I've=20 been <SPAN class=3DSpellE>kinda</SPAN> asking around on <SPAN=20 class=3DSpellE>comp.mail.sendmail</SPAN> about this issue and they are = telling=20 me it is a DNS problem. Well, I know that my mail server can reverse = the IP=20 addresses because if I am logged in and issue a host command with the = IP after=20 it the server is able to produce the proper reverse name. Another user = thought=20 it was because I have no Forward <SPAN class=3DSpellE>dns</SPAN> (a = record) for=20 what the <SPAN class=3DSpellE>IPs</SPAN> are reversed to, but the fact = is I've=20 NEVER had any <SPAN class=3DGramE>A</SPAN> records or anything for my = modem=20 pools. I also have another server running the same version of <SPAN=20 class=3DSpellE>sendmail</SPAN>, 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.=20 So this appears to be an issue only effecting one daemon on one = server. The=20 afflicted server also runs a POP daemon that isn't having any problems = of this=20 type.<o:p></o:p></SPAN></FONT></P> <P class=3DMsoNormal style=3D"TEXT-INDENT: 0.5in"><FONT face=3DArial = size=3D2><SPAN=20 style=3D"FONT-SIZE: 10pt; FONT-FAMILY: = Arial"><o:p> </o:p></SPAN></FONT></P> <P class=3DMsoNormal style=3D"TEXT-INDENT: 0.5in"><FONT face=3DArial = size=3D2><SPAN=20 style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Does anyone have a clue = on this?=20 I'm awfully confused at this point.<o:p></o:p></SPAN></FONT></P> <P class=3DMsoNormal style=3D"TEXT-INDENT: 0.5in"><FONT face=3DArial = size=3D2><SPAN=20 style=3D"FONT-SIZE: 10pt; FONT-FAMILY: = Arial"><o:p> </o:p></SPAN></FONT></P> <P class=3DMsoNormal style=3D"TEXT-INDENT: 0.5in"><FONT face=3DArial = size=3D2><SPAN=20 style=3D"FONT-SIZE: 10pt; FONT-FAMILY: = Arial">Thanks,<o:p></o:p></SPAN></FONT></P> <P class=3DMsoNormal style=3D"TEXT-INDENT: 0.5in"><FONT face=3DArial = size=3D2><SPAN=20 style=3D"FONT-SIZE: 10pt; FONT-FAMILY: = Arial">-Drew<o:p></o:p></SPAN></FONT></P> <P class=3DMsoNormal style=3D"TEXT-INDENT: 0.5in"><FONT face=3DArial = size=3D2><SPAN=20 style=3D"FONT-SIZE: 10pt; FONT-FAMILY: = Arial"><o:p> </o:p></SPAN></FONT></P></DIV></BLOCKQUOTE></BODY></HTM= L> ------=_NextPart_000_0070_01C15553.9F600080-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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