Bug 58201
Summary: | Host name lookup failures in sendmail | ||
---|---|---|---|
Product: | [Retired] Red Hat Linux | Reporter: | Steve Wardell <okapi> |
Component: | sendmail | Assignee: | Florian La Roche <laroche> |
Status: | CLOSED WORKSFORME | QA Contact: | David Lawrence <dkl> |
Severity: | medium | Docs Contact: | |
Priority: | medium | ||
Version: | 7.2 | CC: | justin, redhat |
Target Milestone: | --- | ||
Target Release: | --- | ||
Hardware: | i386 | ||
OS: | Linux | ||
Whiteboard: | |||
Fixed In Version: | Doc Type: | Bug Fix | |
Doc Text: | Story Points: | --- | |
Clone Of: | Environment: | ||
Last Closed: | 2002-03-08 09:42:02 UTC | Type: | --- |
Regression: | --- | Mount Type: | --- |
Documentation: | --- | CRM: | |
Verified Versions: | Category: | --- | |
oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
Cloudforms Team: | --- | Target Upstream Version: | |
Embargoed: |
Description
Steve Wardell
2002-01-10 23:36:54 UTC
Ok, problem's fixed. I think it was DNS. I tried all our DNS servers but all had problems with getting nameserver lookup deferred with sendmail. So I just installed a DNS cache server on the machine, and now it's all perfect. Basically, it's a DNS server that runs on 127.0.0.1 and then I pointed my /etc/resolv.conf to use that local server. The local server uses our office DNS servers, but it's more robust and also caches the results. As soon a I put this thing on, all the pending email whooshed right through. Could this still be looked into with that in mind? I have the exact same problem (host name lookup failures), but (so far) only with mail going to hotmail.com. And, as far as I can tell, all mail going to hotmail.com is affected: [hotdog@mona ~]$ /usr/sbin/sendmail -bp /var/spool/mqueue (11 requests) ----Q-ID---- --Size-- -----Q-Time----- ------------Sender/Recipient------------ g272kX320367 2249 Thu Mar 7 03:54 MAILER-DAEMON (Deferred: Name server: mx07.hotmail.com.: host name lookup f) <ssssss> [...9 more emails going to various hotmail.com-addresses...] g24FZu225755 191 Mon Mar 4 16:35 <bbbbb> 8BITMIME (Deferred: Name server: mx06.hotmail.com.: host name lookup f) mmmm [hotdog@mona ~]$ [Email-adresses have been obscured to protect the innocent] However, I have no problem looking up hotmail.com, both the normal way and with type=mx: [hotdog@mona ~]$ nslookup Default Server: dns1.cybercity.dk Address: 212.242.40.3 > hotmail.com Server: dns1.cybercity.dk Address: 212.242.40.3 Non-authoritative answer: Name: hotmail.com Addresses: 64.4.45.7, 64.4.52.7, 64.4.53.7, 64.4.54.7 64.4.43.7, 64.4.44.7 > set type=mx > hotmail.com Server: dns1.cybercity.dk Address: 212.242.40.3 Non-authoritative answer: hotmail.com preference = 5, mail exchanger = mx10.hotmail.com hotmail.com preference = 5, mail exchanger = mx11.hotmail.com hotmail.com preference = 5, mail exchanger = mx12.hotmail.com hotmail.com preference = 5, mail exchanger = mx13.hotmail.com hotmail.com preference = 5, mail exchanger = mx14.hotmail.com hotmail.com preference = 5, mail exchanger = mx15.hotmail.com hotmail.com preference = 5, mail exchanger = mx01.hotmail.com hotmail.com preference = 5, mail exchanger = mx02.hotmail.com hotmail.com preference = 5, mail exchanger = mx04.hotmail.com hotmail.com preference = 5, mail exchanger = mx05.hotmail.com hotmail.com preference = 5, mail exchanger = mx06.hotmail.com hotmail.com preference = 5, mail exchanger = mx07.hotmail.com hotmail.com preference = 5, mail exchanger = mx08.hotmail.com hotmail.com preference = 5, mail exchanger = mx09.hotmail.com Authoritative answers can be found from: hotmail.com nameserver = ns1.hotmail.com hotmail.com nameserver = ns2.hotmail.com hotmail.com nameserver = ns3.hotmail.com hotmail.com nameserver = ns4.hotmail.com mx10.hotmail.com internet address = 64.4.49.135 mx11.hotmail.com internet address = 64.4.49.199 mx12.hotmail.com internet address = 64.4.50.7 mx13.hotmail.com internet address = 64.4.50.71 mx14.hotmail.com internet address = 65.54.232.7 mx15.hotmail.com internet address = 65.54.232.71 > Also, I can telnet directly to mx02.hotmail.com: [hotdog@mona ~]$ telnet mx02.hotmail.com 25 Trying 64.4.55.135... Connected to mx02.hotmail.com. Escape character is '^]'. 220-HotMail (NO UCE) ESMTP server ready at Fri, 08 Mar 2002 01:26:57 -0800 220 ESMTP spoken here QUIT 221 Service closing transmission channel Connection closed by foreign host. [hotdog@mona ~]$ Only sendmail can't seem to make the connection :-(. For what it's worth, I'm using RedHat 7.0 (kernel 2.2.19-7.0.12 on an i486) with sendmail-8.11.6-2.7.0. Looks all more like Internet problems or DNS issues. Please reopen if you can point at any wrong code within sendmail. Thanks, Florian La Roche This happens on Redhat 7.2 AND on skipjack. DNS failures are occurring, but dig, host, etc resolve the domains fine. There seems to be a problem in sendmail. I too solved the problem by installing a DNS caching server on our system. The problem appears not to be with sendmail as such, but with hotmail being _really_ impatient at some times. Try to telnet to one of the hotmail-mx-servers on port 25 and pretend to want to send an email. Unless you cut'n'paste your commands, you'll get disconnected - as far as I can tell only for being too slow. Sendmail appears to be make some dns-lookup(s) after it connects to mx__.hotmail.com (or any other server), and the dns-lookup)s= needs to happen really fast or hotmail will disconnect the sendmail-process. Therefore, a local DNS caching server will help. Well, at least from the second time, you try to send an email to hotmail, since the caching server still needs to make a lookup the first time :-). I installed a DNS caching software to solve the problem. In this case, the problem is related to sendmail on the Linix machine sending out. The example given of Hotmail.com may be unrelated. By the time your Linux machine has been able to connect to hotmail.com's MX servers on port 25, it's already completed the DNS lookup. The problem is getting the DNS lookup to work succesfully. Once you've made the port 25 connection, everything's fine. |