kyle@xanth.UUCP (Kyle Jones) (10/15/87)
[ Followups go to comp.mail.headers ] In article <2373@megaron.arizona.edu>, whm@arizona.edu (Bill Mitchell) writes: > Increasingly often I've seen mail returned because sendmail's hop count > was exceeded by a valid sequence of hops. As distributed on 4.3, the > hop count (MAXHOP in conf.h) is 17 and I've seen a few sendmails that > have a hop count of 15. Unfortunately, this isn't enough -- some Internet > mail endpoints are more than 17 hops apart. I don't know that there's > any solution for this other than to raise the hop count (which is non-trivial > for binary-only sites). I thought sendmail sources were available for everyone from ucbarpa.berkeley.edu. Is this no longer the case? Sendmail checks the hop count by noting the number of Received: headers in a message. One way to reduce the number of Received: headers is to compact them as a message moves from one organizational domain to the next. For example, suppose a message is delivered to megastron.arizona.edu with the following Received headers: Received: from nansen.ocean.odu.edu by xanth.cs.odu.edu with SMTP (5.51/odu-gateway) id AA24116; Wed, 14 Oct 87 21:04:25 EDT Received: from laplace.ocean.odu.edu by nansen.ocean.odu.edu with SMTP (5.51/odu-lanleaf) id AA00238; Wed, 14 Oct 87 21:04:07 EDT Received: from ICASE.ARPA by laplace.ocean.odu.edu with SMTP (5.51/odu-lanleaf) id AA03459; Wed, 14 Oct 87 21:03:45 EDT Received: by ICASE.ARPA (4.7/1.2a) id AA27641; Wed, 14 Oct 87 21:00:07 edt Before handing the message to sendmail, a program on megastron could crush thees headers down to: Received: from ICASE.APRA by odu.edu with SMTP id AA03459; Wed, 14 Oct 87 21:08:05 EDT Received: by ICASE.ARPA (4.7/1.2a) id AA27641; Wed, 14 Oct 87 21:00:07 edt This would stamp out the redundant information in the headers tacked on by hosts within the same organization. For such a program to be most effective, hosts would have to use the proper format for Received: headers (some don't). kyle jones <kyle@odu.edu> old dominion university, norfolk, va usa
chris@gargoyle.UChicago.EDU (Chris Johnston) (10/16/87)
I thought the hop count was the number of times a message went through the SAME host. If you really want to change it there is a command line flag. cj ihnp4!gargoyle!chris chris@gargoyle.uchicago.edu
leres@ucbarpa.Berkeley.EDU (Craig Leres) (10/20/87)
Stripping received headers is an evil idea. It makes finding broken mail hosts difficult and introduces the possibility of endless mail loops. If the internet has really gotten so big that more than 20 hosts have to fondle a message, then the max hop count needs to be raised. Meanwhile, I feel the correct solution is to find some way to reduce the number of hops. Craig