POP3 "LAST" command

Ken Murchison ken at oceana.com
Tue Jun 24 15:27:52 EDT 2003

David Carter wrote:
> On Tue, 24 Jun 2003, Ken Murchison wrote:
>>RFC 1460 says nothing about maintaining this info across sessions.  It
>>also doesn't prohibit it.  The Cyrus behavior seems perfectly reasonable
>>and correct according to the ancient spec which defines it.
> Yep. I wasn't suggesting the behaviour is unreasonable, just different
> than my installed user agents are used to. It caused one of my beta
> testers a bit of an unpleasant surprise when they arrived this morning :).
>>I'd say that your problem is with fetchmail.  Since LAST is obsolete
>>(quite possibly because of the ambiguity you have seen), fetchmail
>>should default to using UIDL, and then fallback to LAST iff UIDL isn't
>>available.  UIDL was designed specifically to keep track of messages and
>>SHOULD be the preferred mechanism used by clients.
> The fetchmail manpage actually advocates LAST over UIDL on the grounds:
>   But this doesn't track messages seen with other clients, or read
>   directly with a mailer on the host but not deleted afterward.
> so it looks like fetchmail does consider LAST state to be persistent. It
> does however encourage people to use IMAP rather than POP when available.

It sounds like fetchmail was developed against a UW server and assumed 
its behavior to be the standard.  POP3 has no concept of server side 
seen-state, so the fact that UW ties LAST to IMAP's \Seen is fortunate 
at best.

> I guess I'll have to add some monitoring on our existing servers to find
> out just who is using LAST. I'm still tempted to disable LAST altogether
> in our Cyrus installation given the potential for unpleasant surprises.

I don't think this will cause any problems.  I wasn't even aware of LAST 
until I saw your message.

Kenneth Murchison     Oceana Matrix Ltd.
Software Engineer     21 Princeton Place
716-662-8973 x26      Orchard Park, NY 14127
--PGP Public Key--    http://www.oceana.com/~ken/ksm.pgp

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