ISP filters

Some blacklisting programs, the one run by my ISP is an example, allow
individual users to tweak the system to allow selected addresses in
without filtering or to block some without analysis. It took me a
couple of months to get everything set right but now very little gets
lost or through that matters.

If you think you are not getting all the list messages, see if it is
your ISP and whether or not it is tunable on an individual basis.

ER

-----Original Message-----
From: Gordon J. Holtslander [mailto:holtsg@duke.usask.ca]
Sent: Wednesday, April 07, 2004 11:31 AM
To: alt-photo-process-l@sask.usask.ca
Subject: Re: weird. . .

Ryuji is more or less correct. The server that manages this mailing
list
is quite heavily used. Messages that don't get delivered on the "first
try" will wait a significant amount of time before they get another
turn.

The other thing to note is that computers do not have a direct
connection to each other on the internet. Typically an email message
(or
anything sent on the net via tcp/ip) goes through a number of servers to
get from your computer to its destination. These are called hops.

The idea of hopping and arbitrary routing was the founding technology of
the internet.

The length of time a message travels depends on how many hops it must
take, and the response time of each hop. I can use the traceroute
program
to determine what servers and how many hops it takes to get from one
location to another. The route taken is not static - it can change
depending on the traffic of certain parts of the net, and which servers
are up or down.

The time for a message to be sent and and returned is also dependent
upon
the route used. This will vary with every service provider

Currenty trying to do a traceroute to John Campbell's ISP stops
responding
after 17 hops. This isn't typical, but I'm not a traceroute expert.

By comparison I arbitrarily did a traceroute to Ryuji's ISP - it takes
14
hops.

The other thing that really complicates receiving email messages from
this
list, are the number of blacklisting spam blocking services. There are
many that are quite poorly implemented. Mail from this list is
regularly
blocked by at least one of these blacklisting services. There is
nothing
I can do to stop this.

Gord

On Wed, 7 Apr 2004 Grafist@aol.com wrote:

> In a message dated 07/04/04 04:46:34 GMT Daylight Time,
gecko@photogecko.com
> writes:
>
> > Here's an internet paths and protocols question. I'm mightily
> > confounded by this. And confounded minds want to know:
> >
> > At 8:43 CDT, I sent a post ("Leaf and Canon questions") to the
list.
> >
> > At 9:12 a response to the referenced post came in from Sam Wang.
At
> > that time my original post had not shown up in my e-mail files.
> >
> > At 9:34 I fired off a reply to Sam's reply, which hit my inbox at
9:35.
> >
> > Then--and here's the point--at 10:35 MY ORIGINAL POST (sent at
8:43,
> > mind you) popped into my inbox!
> >
> > To quote Dorothy: How can this be!?!
> >
> > It's all just so. . . uncertain.
> ..................................................
> Hi John, This is another ''John''. Seems to be a lot of us around.
Your hitch
> is similar to one I had a couple of weeks back. Postings were getting
thru to
> the list and being sent out to subscribers.....but not to me. However,
the
> quirk cleared up after about a week and everything is back to
'normal'. Maybe
> Ryuji Susuki has mentioned a possible cause in his analysis of the
internet
> paths systems.
>
> ''Mine not to reason why. Mine just to do and.... keep on doing.''
> Apologies for the slightly off topic.
> John Grocott- photographist
>
>

---------------------------------------------------------
Gordon J. Holtslander Dept. of Biology
holtsg@duke.usask.ca 112 Science Place
http://duke.usask.ca/~holtsg University of Saskatchewan
Tel (306) 966-4433 Saskatoon, Saskatchewan
Fax (306) 966-4461 Canada S7N 5E2
---------------------------------------------------------
Received on Thu Apr 8 07:49:04 2004