From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.emacs.gnus.general/21973 Path: main.gmane.org!not-for-mail From: "Edward J. Sabol" Newsgroups: gmane.emacs.gnus.general Subject: Re: UIDL Date: Thu, 18 Mar 1999 10:33:26 -0500 (EST) Sender: owner-ding@hpc.uh.edu Message-ID: <199903181533.KAA18052@alderaan.gsfc.nasa.gov> References: NNTP-Posting-Host: coloc-standby.netfonds.no X-Trace: main.gmane.org 1035159979 25712 80.91.224.250 (21 Oct 2002 00:26:19 GMT) X-Complaints-To: usenet@main.gmane.org NNTP-Posting-Date: Mon, 21 Oct 2002 00:26:19 +0000 (UTC) Cc: ding@gnus.org Return-Path: Original-Received: from fisher.math.uh.edu (fisher.math.uh.edu [129.7.128.35]) by sclp3.sclp.com (8.8.5/8.8.5) with ESMTP id KAA10507 for ; Thu, 18 Mar 1999 10:34:58 -0500 (EST) Original-Received: from sina.hpc.uh.edu (lists@Sina.HPC.UH.EDU [129.7.3.5]) by fisher.math.uh.edu (8.9.1/8.9.1) with ESMTP id JAB08964; Thu, 18 Mar 1999 09:34:09 -0600 (CST) Original-Received: by sina.hpc.uh.edu (TLB v0.09a (1.20 tibbs 1996/10/09 22:03:07)); Thu, 18 Mar 1999 09:34:37 -0600 (CST) Original-Received: from sclp3.sclp.com (root@sclp3.sclp.com [204.252.123.139]) by sina.hpc.uh.edu (8.7.3/8.7.3) with ESMTP id JAA26200 for ; Thu, 18 Mar 1999 09:34:26 -0600 (CST) Original-Received: from alderaan.gsfc.nasa.gov (alderaan.gsfc.nasa.gov [128.183.16.213]) by sclp3.sclp.com (8.8.5/8.8.5) with ESMTP id KAA10490 for ; Thu, 18 Mar 1999 10:34:16 -0500 (EST) Original-Received: (from sabol@localhost) by alderaan.gsfc.nasa.gov (980427.SGI.8.8.8/980728.SGI.AUTOCF) id KAA18052; Thu, 18 Mar 1999 10:33:26 -0500 (EST) Original-To: pinard@iro.umontreal.ca In-reply-to: (message from =?ISO-8859-1?Q?Fran=E7ois_Pinard?= on 18 Mar 1999 07:33:29 -0500) Precedence: list X-Majordomo: 1.94.jlt7 Xref: main.gmane.org gmane.emacs.gnus.general:21973 X-Report-Spam: http://spam.gmane.org/gmane.emacs.gnus.general:21973 Excerpts from [ding]: (18-Mar-99) UIDL by =?ISO-8859-1?Q?Fran=E7ois Pinard?= > Hi, people. I often noticed things like: > > X-UIDL: 3f52d1362f2c1d57ae074fac92f7c9a0 > > Would someone be kind enough to explain what it is, and why it is there? It's a non-standard header inserted by certain POP3 or POP4 servers as a method of storing the information for the `UIDL' POP command. It's like a Message-ID basically. Unfortunately, when the client downloads the e-mail from one of these servers, the e-mail still contains this `X-UIDL:' header. There are at least two known POP servers which do this. The most common of these POP servers will use exactly 32 hexadecimal digits as the value for the `X-UIDL:' header. An example of which is quoted above. A lot of spam, especially from about a year ago or so, was being sent out with `X-UIDL:' headers. I think the intention was to fool these POP servers into displaying the spam e-mails at the top of the recipient's inbox or something like that. Assuming you don't receive your e-mail from a POP server which inserts an `X-UIDL:' header (and doesn't strip this header from the e-mail when downloading it to your client), then you can definitely treat any e-mail with an `X-UIDL:' header as spam *unless* it was `Resent-To:' you. That's an important part caveat. If someone who does get his e-mail from a POP server which inserts these `X-UIDL:' headers resends an e-mail to you or to a mailing list that you subscribe to, then that valid, non-spam e-mail will have an `X-UIDL:' header. Later, Ed