Re: Testing an Email path !

houghi wrote:

Baron wrote:
I agree ! However I didn't know that I had problems until someone
that
needed a document from me phoned to ask where it was. I checked and
it
had been sent over an hour earlier. So I resent the mail whilst I
was
on the phone.... Nothing ! Nothing from his end either. No failure
message, nothing at all.

Kids these days. Thinking that Email must arrive instantly.

I'm well aware that it can take from seconds to days for mail to be
transported through the system.

Email is not a direct form of communication as people think it is.

We kept trying for over an hour. Then suddenly he said that he had
got my mail. The re-send from two minutes before. He sent me one
from his end and seconds later it dropped into my mailbox.

Pretty normal and standard. I do not see this as a problem. The
problem is your perception of email, not email itself.

So what happens with email as a standard is the following. You write
it, then send it to your providers smtp server(A). He accepts it, so
you do not get an error.
After accepting, it will look as to where it needs to go and tries to
deliver it. That other machine(B) accepts it adn looks where it should
be placed. Then the other side will look if it s there.

This is the very basic setup. Often there are some other machines in
between there. Now what can happen is that between (A) and (B) there
can be some delays for several reasons. One is a spam attack, or any
other problem.

So what happens when the one machine can not send it to the other is
wait and try again. First a minute then a few minutes, then an hour
then 4 hours. After 4 hours or so if delivery is still not done will
it send you a warning that the mail has not yet been deliverd, but
PLEASE DO NOT SEND IT AGAIN. What happens is that people then send it
again, because they do not read.

Now imagine somebody actualy not re-sending it and thus letting a
potential overloaded server do its job and not add more load to it, it
will try for up to 4 days and only then tell you that delivery is not
possible.

As long as that has not happened, the mail is not 'gone' it is still
on the SMTP sever who is trying to send it. It is in a queue.

Now each message gets a new time and time gets longer over time for a
very good reason. So this will mean that once a message gets through,
it is highly likely that a message you send later will arrive earlier.

Yes I agree ! I have had messages turn up out of order a number of
times.

First test the smtp with telnet and see if you can send mail there:
telnet server.example.com 25
mail from: houghi
rcpt to: user@xxxxxxxxxxx
data
test

Nothing only "?Invalid command"

Huh? No 'telnet'? I thought that was installed on every machine as a
standard. If not, please install it. You can not do any network
testing without it.

Yes its installed. When the server is working I get quite different
responses.

And then see what happens.

To test the pop3, you do
telnet server.example.com 110
user login
pass password
list
last
top 0 0
quit

And see that there is mail in there.

Same here "Name or service not known"

If I do the same to my own server I get the expected response !
Actually I get "ogin" the "L" is missing.

That is not the same. That is different. One tells me that telnet is
not installed, the other tells me that port 110 is not known there.

I hope you understand that the domain names are not real. I do have NO
idea what they must be in your case.

Yes I do. The DNS lookup works fine. When the server is working it
come back with the dotted quad.

I find it odd that first the command telnet does not exist and in the
second part it does. Please copy and paste whatever you did. Do not
change server names (I can look it up anyway, but I am too lazy) Just
change the emailadress, if possible by just adding .invalid to it.

When the service disappears telnet fails with "?Invalid command"
Otherwise I get expected responses.

And again, I think your provider (and theirs) where right in saying
there was no problem. If you want direct communication, right away
instantly, email is NOT the correct tool.

No I am not looking for instant communication. I have voice and FAX
services for that.

The reason for delay can be various and are to be expected. That is
why SMTP has these delays build into it. I have seen mail pass 7 or 8
different servers and between each one there was a delay. The more
machines are used, the more can go wrong.

Where things go wrong is something you can see in the headers. The
most common reason for a delay nowadays is a LOT of spam arriving at
the same time at the provider, so that there are delays and even
timeouts.

I couldn't agree more !

And as you recieved your mail as it was supposed to, I would say the
system worked as expected. (Did I mention that email wasn't direct
communication?)

You did ! But mail was not received as it was supposed to ! So there
are no headers to show. I wish there were ! As you say the path can
be traced through those. But since the mail just disappears, and from
both ends, I've nothing to track anything with.

houghi

I do understand and agree that a problem at my end could explain what is
happening ! If so why does everything work properly when I switch
ISP ? Web mail works either way. The only difference there is the use
of a browser and protocol. I can send or rather try to send a mail via
SMTP using my ISP's server and be watching the receiving machine via
web mail and nothing ever arrives.

--
Best Regards:
Baron.
.

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