x-uidl & message ID
Alex Rodriguez
Hi all. Well, I have a question regarding the next two lines:
X-UIDL: 3ad9e11076bb2649457d14c7895656a9
Message-Id: <1997122016...@catalog.com>
My question is: Ho w can I find what these lines mean? Any body knows? I
get these two lines by looking into a message through the bla bla icon in
Eudora.
Any response will be highly appreciated.
Thanx a million in advanced.
Alex
Ken Simler
On Sun, 21 Dec 1997, Damien Burke wrote:
> On Sat, 20 Dec 1997 11:34:38 -0000, "Alex Rodriguez"
> <al...@relaypoint.net> wrote:
>
> >Hi all. Well, I have a question regarding the next two lines:
> >
> >
> >X-UIDL: 3ad9e11076bb2649457d14c7895656a9
> >Message-Id: <1997122016...@catalog.com>
> >
> >
> >My question is: Ho w can I find what these lines mean?
>
> X-UIDL will almost always indicate that this is a spam. Very
> rarely it appears in mailing list mail (so I'm told). One of my
> anti spam filters chucks any mail with this header that doesn't
> also have a 'X-Mailer: Pegasus...' header entry (on the basis
> that I have *one* legit. mail with an X-UIDL header, and it was
> from a Pegasus user). Quite happy to be corrected on this :)
Then I hope this will make you quite happy...
UIDL stands for Unique ID Listing, and it's something that most POP3
servers and clients (and all *good* POP3 servers and clients) use to keep
track of individual messages. For details, read RFC 1725
<http://ds.internic.net/rfc/rfc1725.txt>.
You may have one legit email with an X-UIDL header, but someone using a
POP3 server that supports UIDL would have such headers on *every* message,
so it doesn't work as a spam criterion for many people, and it's just
plain coincidence that it does work for you.
Your Pegasus & UIDL criteria may work as spam filters for you, but I
really hope you don't recommend them to anyone else. Many people use POP3
servers that support UIDL, and many legit users use Pegasus because it is
a very good, free, email program. There are far more reliable ways to
filter spam, based on headers that really matter. They're posted
frequently in this newsgroup.
-Ken
Damien Burke
>Hi all. Well, I have a question regarding the next two lines:
>
>
>X-UIDL: 3ad9e11076bb2649457d14c7895656a9
>Message-Id: <1997122016...@catalog.com>
>
>
>My question is: Ho w can I find what these lines mean?
X-UIDL will almost always indicate that this is a spam. Very
rarely it appears in mailing list mail (so I'm told). One of my
anti spam filters chucks any mail with this header that doesn't
also have a 'X-Mailer: Pegasus...' header entry (on the basis
that I have *one* legit. mail with an X-UIDL header, and it was
from a Pegasus user). Quite happy to be corrected on this :)
Message-id is just that - an identifier for this particular
piece of mail. If most mail programs were threaded and referred
to mails when replying it would be very useful. As it is, not
many make use of it for anything other than a unique reference
to the mail when saving it locally. If it doesn't have a @ in it
it's 'broken', not complying with the standards (no particular
surprise - lots of mail clients are 'broken' in this way). But
an empty one e.g. <> is almost always an indicator of a spam.
--
Damien Burke (add k to end of address if replying)
Damien Burke
>UIDL stands for Unique ID Listing, and it's something that most POP3
>servers and clients (and all *good* POP3 servers and clients) use to keep
>track of individual messages.
Yes, I know.
>You may have one legit email with an X-UIDL header, but someone using a
>POP3 server that supports UIDL would have such headers on *every* message,
My POP3 server supports UIDL, my mail client uses it and as I
say - only *one* message with such a header in it. Are you
actually looking at headers or just shooting in the dark here?
Damien Burke
>You may have one legit email with an X-UIDL header, but someone using a
>POP3 server that supports UIDL would have such headers on *every* message,
Right, I've checked a few different servers and have found one
that adds X-UIDL headers to messages as they arrive, unless the
message already has one. Lots of spam does indeed have such a
header before hitting the server - the result being that UIDL
listings from the server then show the fake UID that was in the
spam, which is often just a piece of text and is the same for
many different spams (rendering the use of UIDL to give a unique
ID somewhat questionable - I hope no mail client relies on that
alone!).
>so it doesn't work as a spam criterion for many people, and it's just
>plain coincidence that it does work for you.
I agree, if your POP3 server is doing this to incoming mail it
ain't going to be much use for you. However, it's easy enough to
check a few of your mails and see if your server is doing this.
If it isn't, then this may be a useable filter.
>Your Pegasus & UIDL criteria may work as spam filters for you, but I
>really hope you don't recommend them to anyone else. Many people use POP3
>servers that support UIDL, and many legit users use Pegasus because it is
>a very good, free, email program.
Reading that again you seem to think that I'm throwing away mail
from Pegasus users. I'm not. I quite clearly said that I was
ditching it if it had X-UIDL but also *didn't* have an
'X-Mailer: Pegasus...' header.
Damien Burke
On Sun, 21 Dec 1997 17:20:39 GMT, adam....@pobox.com (Adam
Kippes) wrote:
>I was wondering that about *you*... I was also wondering what Pegasus
>(or any mail client) had to do with it
Because the single legit message I've received with it also
advertised that it was sent by Pegasus mail. I suspect now this
was by the by because that mail was forwarded to me - I'm
guessing the forwarder's server had added the X-UIDL line.
>, as it happens to me with Eudora,
>Pegasus, and MS IM; I haven't checked with Agent, but I'd be very
>surprised if the header didn't appear there, too.
See my other post. Also note I don't use Agent for mail...
>This silly piece of nonsense- only spam has X-UIDL
You'll note I didn't state it was a 100% proven fact and
welcomed correction.
> - has been floating
>around the anti-spam fanatic circles for ages; one can't help but wonder
>how much legitimate mail has been lost because of it.
None here.
>Oddly enough, I've never noticed any anti-spam fanatic explain *why*
>only spam would have such a header.
Because some piece of spamming software includes it in the
outgoing spam. Quite simple.
Ken Simler
On Sun, 21 Dec 1997, Damien Burke wrote:
> On Sat, 20 Dec 1997 23:35:57 -0500, Ken Simler
> <k...@mango.human.cornell.edu> wrote:
>
> >You may have one legit email with an X-UIDL header, but someone using a
> >POP3 server that supports UIDL would have such headers on *every* message,
>
> Right, I've checked a few different servers and have found one
> that adds X-UIDL headers to messages as they arrive, unless the
> message already has one.
Oh, you actually tried another server. Now, what was that smartass crack
about "...are you actually looking at headers or just shooting in the dark
here?" I don't see it in any of your quoted text.
> >Your Pegasus & UIDL criteria may work as spam filters for you, but I
> >really hope you don't recommend them to anyone else. Many people use POP3
i> >servers that support UIDL, and many legit users use Pegasus because it
is
> >a very good, free, email program.
>
> Reading that again you seem to think that I'm throwing away mail
> from Pegasus users. I'm not. I quite clearly said that I was
> ditching it if it had X-UIDL but also *didn't* have an
> 'X-Mailer: Pegasus...' header.
Right. My mistake. You're not trashing mail from Pegasus users, but from
everyone else, if the message also happens to have a (potentially valid)
X-UIDL header. As I said before, whatever works for you.
Personally, this week I'm spam-filtering everything that has the letter
'z' in the Message-ID: header. Been having a lot of problems with those
lately.
-Ken
Damien Burke
>Oh, you actually tried another server. Now, what was that smartass crack
>about "...are you actually looking at headers or just shooting in the dark
>here?" I don't see it in any of your quoted text.
It was merely a question - no need to get your knickers in a
twist. Did YOU go away and try and find a server that *didn't*
add that to headers?
>Right. My mistake. You're not trashing mail from Pegasus users, but from
>everyone else
READ MY LIPS. My server does NOT add X-UIDL to incoming mail. I
have had ONE legit mail with such a header. My filter would let
that through. You're really not keeping up with this are you?
Ken Simler
On Mon, 22 Dec 1997, Damien Burke wrote:
> READ MY LIPS. My server does NOT add X-UIDL to incoming mail. I
I understand it just fine. All I have said all along is that it works for
you, but be cautious about recommending it to anyone else. Also, unless
you're the one who manages your POP3 server, you might be in for a rude
surprise yourself when your ISP changes it without telling anyone.
*plonk*
-Ken
Damien Burke
>I understand it just fine. All I have said all along is that it works for
>you, but be cautious about recommending it to anyone else.
Leaving aside the bits where you were plain wrong of course.
> Also, unless
>you're the one who manages your POP3 server, you might be in for a rude
>surprise yourself when your ISP changes it without telling anyone.
I think I *just might* notice all incoming mail suddenly
triggering kill rules.
>*plonk*
Run away if you must. Good riddance.
Ken Simler
On Mon, 22 Dec 1997, Randall Gellens wrote:
> In article
> <Pine.A32.3.95.971220...@mango.human.cornell.edu>, Ken
> Simler <k...@mango.human.cornell.edu> wrote:
>
> > UIDL stands for Unique ID Listing, and it's something that most POP3
> > servers and clients (and all *good* POP3 servers and clients) use to keep
> > track of individual messages. For details, read RFC 1725
> > <http://ds.internic.net/rfc/rfc1725.txt>.
> >
> > You may have one legit email with an X-UIDL header, but someone using a
> > POP3 server that supports UIDL would have such headers on *every* message
>
> If a POP server supports UIDs, that means it handles the UIDL command. It
> doesn't mean it adds an "X-UIDL" header to mail. Some POP servers which
> support UIDs add an X-UIDL header, others do not. It depends on the
> underlying message store, and the delivery mechanisms. In some cases, the
> X-UIDL header is really the only way to assign a UID to a message and have
> it stick around. In other implementations, no header is needed.
Right. I confused the two in my post. Certainly, whether or not an
X-UIDL header is added depends entirely upon the particular POP3 daemon
and its configuration. For example, if I recall correctly, qpopper 2.x
does add X-UIDL:, whereas UW's ipop3d does not. Both support the UIDL
command.
Thanks for clarifying this for everyone.
-Ken
Ken Simler
In article <34a014df...@news.demon.co.uk>,
news_...@jetman.demon.co.u wrote:
>On Mon, 22 Dec 1997 15:38:22 -0500, Ken Simler
><k...@mango.human.cornell.edu> wrote:
[snip]
>>*plonk*
>
>Run away if you must. Good riddance.
Hardly running away. But maybe I'll just killfile this thread, so that I
can be sure not to miss all your valuable contributions to this newsgroup.
-Ken