POP3 "LAST" command

David Carter dpc22 at cam.ac.uk
Tue Jun 24 12:54:49 EDT 2003

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  Since LAST is obsolete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.

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.

David Carter                             Email: David.Carter at ucs.cam.ac.uk
University Computing Service,            Phone: (01223) 334502
New Museums Site, Pembroke Street,       Fax:   (01223) 334679
Cambridge UK. CB2 3QH.

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