[H-GEN] POP3, v42.bis, and the Facts of Life

[W. Sierke]

[ Humbug *General* list - semi-serious discussions about Humbug and
Unix-related topics. ]

Hi,

I'm currently having occasional (but all-too-frequent) problems collecting
my e-mail (using a client that retrieves directly from a number of POP3
servers). The problem manifests itself as non-recoverable timeouts
(currently set to 60s, but I've attempted successive retries of at least
10x, i.e. a ten minute timeout). There are two POP3 servers involved, one
over about 16 hops (in Adelaide) and one over about 6 hops (I think the
server is in Sydney). Generally the routes appear to diverge after the third
node.

On occasion a traceroute has shown a problematic router (typically on the
Adel/Melb connection). Once I saw the packets ending up in Hobart! Most of
the time, however, no other problems are apparent. I can browse, ftp,
download files quite happily, but trying to collect my e-mail, get these
%#$@ timeouts. Eventually, with enough perseverance, it will succeed. (The
other day it took about 90mins!)

I have been advised to disable modem compression, along with the advice that
(v.42bis) makes the connection more susceptible to noise, and additionally
that POP3 is fickle and gets fouled as a result. Hmmm! (As the reader has
picked up by now, I'm talking about a dial-up modem connection).

I remain unconvinced, and demand that the Internet works the way I both want
and expect it to! (stamping of feet).

In the meantime, I pose the following question to the venerable reader:

1) What is the consensus regarding use of v.42bis over a dial-up PPP
connection? (All I found in the HOWTOs was stuff about the futility of
compressing compressed files, yada-yada-yada.)
2) To what extent is the POP3 protocol reliable? (ie. is it guaranteed to
succeed if left to its own devices for sufficient time, save for
insurmountable network faults?)
3) What are the indicators of failure? (ie. will a POP3 server give up, and
how would you know that it had?)
4) What tools are available to identify points of network congestion? (and
are there ISPs which are less prone to it, or is it a fact of Life On The
Australian Internet?)


Wayne




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