ane@hal.UUCP (Aydin "Bif" Edguer) (08/09/88)
HELP! Environment: I am currently running sendmail 5.59 on a VAX 11/750 under 4.3 BSD. I am also running named 4.8. Problem: When sending mail to a particular site, I receive the following error: 550 hostname... Host unknown Fact: The hostname exists and has a valid number. Verified by running nsquery and nslookup. Fact: Other internet hosts can be found and mail sent via SMTP. Verified by sending mail using the verbose option. (numerous sites and times) Fact: I use the following rules to isolate tcp sites: > # Well it isn't a "known" host lets try to find it > R$*<@$+.UUCP>$* $1<@$2>$3 Just drop the .UUCP > # Look for host name using named > R$*<@$+>$* $:$1<@$[$2.$]>$3 ask named to resolve > R$*<@$+.>$* $:$1<@$[$2.$]>$3 recheck unresolved names > # Send mail via tcp to known hosts > R$*<@$+>$* $#tcp$@$2$:$1@$2$3 user@domain The hostname lookup SUCCEEDS! Verified by running sendmail -bt ruleset 0 user@host where host is a known alias. The hostname is converted to its canonical hostname! Fact: I do not understand how named and sendmail can resolve the name AND the host still be UNKNOWN! Verified by this posting :-) I am at wit's end. Help me please. Wanted: Solutions to the problem or Suggestions on how to isolate the problem Aydin Edguer ane@hal.cwru.edu
hakanson@mist.cs.orst.edu (Marion Hakanson) (08/09/88)
In article <277@hal.UUCP> ane@hal.cwru.edu (Aydin "Bif" Edguer) writes: >Environment: >I am currently running sendmail 5.59 on a VAX 11/750 under 4.3 BSD. >I am also running named 4.8. >. . . >Fact: >I do not understand how named and sendmail can resolve the name AND the >host still be UNKNOWN! >Verified by this posting :-) >. . . >Aydin Edguer >ane@hal.cwru.edu This rather surprising behavior can occur when (for example) someone has an MX record pointing to an unknown host. Sendmail reports the original destination host as being unknown, when it is actually the MX-er which cannot be resolved. Get into nslookup, "set type=MX" and look at what MX records exist for that host. To find the offender, "set type=A" and try each of the MX hosts shown above. Needless to say, a better diagnostic from sendmail would be greatly appreciated. -- Marion Hakanson Domain: hakanson@cs.orst.edu UUCP : {hp-pcd,tektronix}!orstcs!hakanson
karl@triceratops.cis.ohio-state.edu (Karl Kleinpaste) (08/09/88)
hakanson@mist.cs.orst.edu writes: >I do not understand how named and sendmail can resolve the name AND the >host still be UNKNOWN! This rather surprising behavior can occur when (for example) someone has an MX record pointing to an unknown host. It can also happen if there is inconsistent data among a domain's various nameservers out there. In the last several months, I have caught 3 or 4 instances where mail to some.site.domain got bounced with `host unknown,' but when I later made a fast check for the host, I got valid A or MX records. On checking ALL of the nameservers for the given host, 2 out of 3 had the correct data, the 3rd gave me an authoritative denial of existence. Oops. Can you guess on which nameserver my machine managed to have a grip when that mail was trying to go through? I generally try to duplicate the inconsistency in a typescript that I can then send to the person identified in the SOA record. --Karl