Post by r***@yahoo.comI have a problem sending emails with 600kb attachment to one sight.
Where is PPP in this mix, and why are you posting to
comp.protocols.ppp about an email or networking problem?
Some hints about what sort of computer you're using, what operating
system, what protocols, and how they're configured would be
appreciated. Better still if you could indicate something about what
you've tried to do to investigate the problem.
Post by r***@yahoo.comEmails with smaller
attachments get there.
Some sites have intentional size limits on email messages. This
_could_ be what you're running into. Generally speaking, sending huge
attachments is impolite, and you should send a link instead so that
the recipient can download the file if he feels like it (rather than
be forced to accept the giant quota-chewing blob in the middle of his
mailbox).
Post by r***@yahoo.comconversation with mail.mullen.com[208.12.118.16] timed out while
sending message body)
I am able to send and recieve emails with 600KB to yahoo.com. Why
would it be a problem sending to mullen.com?
Have you contacted the postmaster there?
Post by r***@yahoo.comI read postings and they mentioned that by lowering the MTU that might
help, but I am to send emails to yahoo. Is Yahoo system configuration
able to handle my emails, but not mullen.com?
Possibly. There's little way for us to know.
At a 600KB limit, it seems extremely unlikely to me that this is
related to MTU. MTU problems tend to affect things pretty early in
the connection (around the third or fourth packet sent).
Possibilities include:
- There's a broken NAT or stateful firewall somewhere in the middle.
It takes you so long to transfer that large file that this device
discards the flow state and loses the ability to transfer your
packets.
This is fairly likely, diagnosing it will be very hard, and fixing
it nearly impossible. The main symptom is that the TCP acks
coming back will just cruise along for quite a while in steady
state and then just ... stop.
- The administrator of that site just doesn't want you to send giant
email messages and has put some sort of restriction in place.
Have you asked?
- Bugs in the TCP implementation on one side or the other. This is
also hard to diagnose, and involves studying the transfers
carefully. It's sometimes hard to discern this problem from a
broken NAT.
- If your entire network link gets stuck when this happens -- no
more packets in and out, not even a ping -- then it's possibly
some sort of low-level problem. Having a PPP link with
misconfigured serial flow control parameters can have this sort of
effect.
None of this seems to be directly related to PPP.
--
James Carlson, KISS Network <***@sun.com>
Sun Microsystems / 1 Network Drive 71.232W Vox +1 781 442 2084
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