Re: [twsocket] mx lookup
"5 mail servers each" More like several hundred, many cluster groups. They use load balancing so you really don't see the true number from a MX lookup. Darin -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of DZ-Jay Sent: Thursday, May 08, 2008 9:07 AM To: ICS support mailing Subject: Re: [twsocket] mx lookup Wilfried Mestdagh wrote: > Hello, > > To find out which is the smtp server I have to send mail to for a > particular domain I can use the MXPreference[n] property of DnsQuery > component. But in what case there can be multiple results ? (I tryed a > few and get only 1 result 'answer#1 in demo program'). RFC specifies that entries can have multiple MX records with a preference number. The lower the value, the higher the preference. This is mostly used by large ISPs that have multiple hosts processing mail, for fault tolerance or load balancing. For example, AOL and Earthlink have about 5 mail servers each, all with their own MX record. dZ. -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] mx lookup
Wilfried Mestdagh wrote: > thanx Dz and Arno, > > some more questions. What about the MXPreference? For example if I do a > mx lookup for sonal.be it returns mail.sonal.be with value 10 and > mxl.sonal.be with value 50. Does this mean one of the 2 is preferred? > and if so the one with the lowest value or the highest one? The one with the lowest numerical value is the preferred one. In your case, "mxl.sonal.be" may be there for fault tolerance, in case the "main" server is down. When they all have the same value, it's usually for load balancing, so you are free to pick the one with the lowest latency. dZ. -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] mx lookup
Sorry forget this mail I did not read the answer from DZ good :( --- Rgds, Wilfried [TeamICS] http://www.overbyte.be/eng/overbyte/teamics.html http://www.mestdagh.biz Thursday, May 8, 2008, 16:42, Wilfried Mestdagh wrote: > thanx Dz and Arno, > some more questions. What about the MXPreference? For example if I do a > mx lookup for sonal.be it returns mail.sonal.be with value 10 and > mxl.sonal.be with value 50. Does this mean one of the 2 is preferred? > and if so the one with the lowest value or the highest one? > --- > Rgds, Wilfried [TeamICS] > http://www.overbyte.be/eng/overbyte/teamics.html > http://www.mestdagh.biz -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] mx lookup
thanx Dz and Arno, some more questions. What about the MXPreference? For example if I do a mx lookup for sonal.be it returns mail.sonal.be with value 10 and mxl.sonal.be with value 50. Does this mean one of the 2 is preferred? and if so the one with the lowest value or the highest one? --- Rgds, Wilfried [TeamICS] http://www.overbyte.be/eng/overbyte/teamics.html http://www.mestdagh.biz -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] mx lookup
Wilfried Mestdagh wrote: > Hello, > > To find out which is the smtp server I have to send mail to for a > particular domain I can use the MXPreference[n] property of DnsQuery > component. But in what case there can be multiple results ? (I tryed a > few and get only 1 result 'answer#1 in demo program'). RFC specifies that entries can have multiple MX records with a preference number. The lower the value, the higher the preference. This is mostly used by large ISPs that have multiple hosts processing mail, for fault tolerance or load balancing. For example, AOL and Earthlink have about 5 mail servers each, all with their own MX record. dZ. -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] mx lookup
Hallo Wilfried, > To find out which is the smtp server I have to send mail to for a > particular domain I can use the MXPreference[n] property of DnsQuery > component. But in what case there can be multiple results ? (I tryed a > few and get only 1 result 'answer#1 in demo program'). > > What is the MXExchange[n] property for ? I'm not sure whether the standard DnsQuery component returns multiple MX entries. If memory serves I once used Holger's component in ICS sub directory internet\HLembke for that purpose which works fine: Request ID : 2 ID : 2 ResponseCode : 0 OpCode : 0 Authoritative : 0 Truncation : 0 RecursionAvailable : 1 QDCount: 1 ANCount: 3 NSCount: 0 ARCount: 6 ResponseLen: 193 QuestionName : microsoft.com QuestionType : 15 QuestionClass : 1 MailExchange: maila.microsoft.com MailExchange: mailb.microsoft.com MailExchange: mailc.microsoft.com Item for: microsoft.com MailExchange: maila.microsoft.com 10 Item for: microsoft.com MailExchange: mailb.microsoft.com 10 Item for: microsoft.com MailExchange: mailc.microsoft.com 10 Item for: mailb.microsoft.com DnsQueryA:131.107.115.215 Item for: mailb.microsoft.com DnsQueryA:205.248.106.30 Item for: mailc.microsoft.com DnsQueryA:131.107.115.214 Item for: mailc.microsoft.com DnsQueryA:205.248.106.32 Item for: maila.microsoft.com DnsQueryA:205.248.106.64 Item for: maila.microsoft.com DnsQueryA:131.107.115.212 Response dump (193 bytes): <0><2><129><128><0><1><0><3><0><0><0><6><9>mic rosoft<3>com<0><0><15><0><1><192> <12><0><15><0><1><0><0><1>/<0><10><0><10><5>ma ila<192><12><192><12><0><15><0><1><0><0><1>/<0> <10><0><10><5>mailb<192><12><192><12><0><15><0> <1><0><0><1>/<0><10><0><10><5>mailc<192> <12><192>C<0><1><0><1><0><0><9><237><0><4><131>ks <215><192>C<0><1><0><1><0><0><9><237><0><4><205><248>j <30><192>Y<0><1><0><1><0><0><13>+<0><4><131>ks <214><192>Y<0><1><0><1><0><0><13>+<0><4><205><248>j <192>-<0><1><0><1><0><0><1>/<0><4><205><248>j @<192>-<0><1><0><1><0><0><1>/<0><4><131>ks <212> > > -- > Rgds, Wilfried > http://www.mestdagh.biz -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
