jimr@maths.su.oz.au (Jim Richardson) (05/30/90)
Correctly addressed mail to some sites in Switzerland is sometimes being bounced, apparently because of an error in the nameserver configuration. For example, ethz.ch has the following MX records: ethz MX 10 chx400.switch.ch ethz MX 20 relay.EU.net Now chx400.switch.ch has an A record, but relay.eu.net does not seem to exist. It has no A record; the only information in DNS relating to it seems to be relay.eu.net preference = 10, mail exchanger = mcsun.eu.net If chx400 is down or unreachable, sendmail tries relay.eu.net, and the message is returned to the sender with a "Host unknown" error. Note that sendmail should *not* be expected to take note of a "second level" MX record like the one for relay.eu.net. Should the ethz preference 20 MX record (and other similar records for other Swiss domains) refer to mcsun.eu.net instead of relay.eu.net? Mail to the domain contact and the postmaster hasn't had any apparent effect. Apologies in advance if I've misinterpreted the problem and it is at my end somehow: if so, advice would be appreciated. -- Jim Richardson Department of Pure Mathematics, University of Sydney, NSW 2006, Australia Internet: jimr@maths.su.oz.au ACSNET: jimr@maths.su.oz FAX: +61 2 692 4534
piet@MCSUN.EU.NET (Piet Beertema) (05/31/90)
I think what should have happened was that "relay.eu.net" should have been a CNAME for mcsun.eu.net... No, that was never intended and it would be wrong too. The name relay.EU.net is only used in conjunction with the gateway function(s) of mcsun.EU.net: in that case mcsun will generate header From: lines of the form From: host!user@relay.EU.net or From: user%node.bitnet@relay.EU.net If relay.EU.net were a CNAME for mcsun.EU.net, these forms would be incorrect (can't remember right now in which rfc to find it) and sendmail 5.61 is known to generate a "Cannot prescan canonical hostname" error if you use it that way. Since a CNAME RR would be wrong and the real hostname is mcsun.EU.net, there is no A RR, but an MX RR for relay.EU.net pointing to mcsun.EU.net to ensure proper routing of replies. Piet
del@thrush.mlb.semi.harris.com (Don Lewis) (06/01/90)
In article <9005311505.AA09588@Gipsi.Gipsi.Fr> philipp@GIPSI.GIPSI.FR (Philippe Prindeville) writes: >I think what should have happened was that "relay.eu.net" should >have been a CNAME for mcsun.eu.net... Obviously, you can't have >MXes that point to MXes... > >-Philip That's better, but the MX should really point to the canonical hostname, not an alias. -- Don "Truck" Lewis Harris Semiconductor Internet: del@mlb.semi.harris.com PO Box 883 MS 62A-028 Phone: (407) 729-5205 Melbourne, FL 32901