>"kpop" moves the actual authentication onto the client and uses kerberos
>the way it's supposed to be used. It's still not ideal;
>it only handles authentication and doesn't secure the session
>which would be vulnerable to tcp hijacking. Also, with k4, it's
>only des. There's also a whole new proxy issue if you need
>AFS tokens in the mail server.
FWIW, I have code that does GSSAPI authentication with POP for Kerberos 5,
which _also_ does session encryption (it uses SASL; this is the
standards-based way to accomplish this).
>> >
>> >Typically, popserver users connect and login very frequently
>> >(perhaps every minute) just to check if they have new mail.
>> >All this login activity soon swamps a popserver that is
>> >using AFS login authentication.
I always found that if you're using ka_UserAuthenticateGeneral() that's
doing WAY too much work that generally isn't necessary for POP. Oh,
if you're verifying Kerberos passwords _that_ way, you also have a
even more nasty security vulnerability than sniffable passwords :-/
>It might also be attractive to offer an additional "mail notification"
>service that isn't quite so expensive. It's not hard to teach a mail
>server how to send zephyrgrams upon mail delivery, for instance.
>It might be entertaining today to figure out how to use ICQ or
>"instant messanger" or whatever today.
The problem I always had with zephyr was that it was nearly impossible
to set up (that's aside from the problem of it being wedded to V4).
I spent a week on it, but I never really got it working.
>I find myself curious as to how these sites that presumably keep pop
>mailboxes in AFS handle mail forwarding. Do you handle mail forwarding
>on the pop servers? Do you allow programs, such as procmail and
>vacation? How do you handle AFS tokens and pags for such programs? If
>you haven't thought about this, and are using sendmail or something
>similar, what happens if a user creates a .forward in their home
>directory? Is it honored?
We don't keep our mailboxes in AFS space, but we do currently honor
.forward files (but they can't run arbitrary programs, only ones out of
a particular list ... and binaries we control). What will probably happen
in the future is that we will get rid of .forward files in home directories
and require users to run a special program to set up mail forwarding.
--Ken
