Mailinglist Archive: opensuse (3337 mails)

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Re: [SLE] SMTP authentication was re:[SLE] mail sending and Postfix was OT: Posting from another unsubscribed address for a subscriber?
  • From: "Hylton Conacher (ZR1HPC)" <hylton@xxxxxxxxxxxx>
  • Date: Thu, 27 Apr 2006 16:32:52 +0200
  • Message-id: <4450D614.20005@xxxxxxxxxxxx>
Carlos E. R. wrote:

The Tuesday 2006-04-25 at 12:18 +0200, Hylton Conacher (ZR1HPC) wrote:

...

It sends email to the server you have told it to send to. Distance or
ownership has nothing to do. Nor has the smtp server got to connect or
disconect after or before you receive mail from the pop server(s).

So basically the server I enter as the Mozilla SMTP server receives the mail
from me and sends it to the destination or next relay before the destination,
no questions asked?


The first SMTP sever may ask questions, of course. Any SMTP server in the chain, except the one of the destination address may ask for authentication of some sort; ie, your ISP SMTP server may ask for it, because it will _relay_ your mail to somebody else......
OK, understood. What tyoe of authentication could a SMTP server say 3 down the line ask for? Would its request be answered by the second SMTP server or would SMTP-3 try and contact the original dialup server which may not be currently connected?

Time to visit an inet cafe and Google SMTP authentication methods.


...........Also, if to tell Mozilla to send the email you write on the gmail account through gmail smtp server (bypassing your ISP smtp server), this will also request some ID.
Well when I tried sending mail using the GMail SMTP it didn't seem to work, although tat could have been due to user education. As it didn't go through I figured that it probably needed an ID on me ie I needed to log on first or send from my GMail account. I cannot stay connected whilst I read + reply to SLE mesages.

Given that I like to/have to read my email offline is there a way to use teh GMail SMTP server to send email that does not originate from a GMail address? If someone has some info or a tutorial, I'd be most interested.

It would be rare that the second server asked for ID, but it could happen: for instance, in a private network users send to a certain local SMTP server. This one sends to another one on their ISP, who request auth from the private server (but not from the user: that is impossible).
Right, so if I understand correctly, having my own local SMTP server might not alleiate the problems I am experiencing now as again the email FROM header is different to te dialup connection account, and they would have to be the same for the ISP SMTP server to accept it
OR
As the ISP SMTP server is receiving mail from another SMTP server(my local one) will it not authenticate each email sent on te above criteria but do it another way?

The method used for authentication varies. An ISP can simply validate by the IP number you use. Or, it can also see that you retrieved email from them, say, three minutes ago from this IP (POP before SMTP). Or it can ask for a login/password pair.
Are these methods also used if the sender is a SMTP server or are different criteria used? ie see above just below OR.

In other words: SMTP servers that relay email to some other smtp server should normally use some kind of authentications. Those servers of the destination address will not.
OK understood that any of the SMTP servers can request authentication, except the destination SMTP server.

Another clarification: The minimum is two smtp servers in the chain. One gets the email from you, the other one receives it for the addressee. Depending on the setup, there can be intermediaries on both sides. Each one normally adds a "Received" header to the email, and you can read them (try: it is instructive).
mmm, I've seen email headers and understand this. What i didn't know was that there are normally only a maximum of 2 SMTP servers ie sender and receiver.

This relay server will normally send all that email direct to the
destination address, no intermediaries. The destination server can not do
authentification, because the email is for him: he can not reject it,
unless he thinks it is spam or virus or such.

AAAAHHHH Right, my thick headedness has cleared considerably! :)
I thought there were intermediaries as if a link to a country goes down then
the packet would need to be routed to on another path via an intermediary
host.


No, intermediaries happens in complex setups for reasons different that distance. But there might be none at all.
OK

I thought the intermediary and destination server did authentication to cut
back on SPAM.

No, they do other kinds of tests, but they can not ask a login/password from you, they doesn't "see" you.
OK, so , assuming a mail has to take the long path to get to the email destination and therefore goes from local SMTP to ISP SMTP to intermediary SMTP to destination SMTP and that the intermediary SMTP needs authentication. However because it cannot see my local server, due to it having dropped its dialup connection or whatever, it does other tests to obtain authentication.

OK, what I have managed to so far partly confirm is that my ISP is currently
doing authentication on email the SMTP server receives from the ISPs users and
thus they are prohibiting me from sending email from my own domain that is not
held/registered by them, eventhough I hold a dialup and different email
account with them.

Right! :-)
Can this type of authentication be got around or changed ie what other types could I request them to rather ask me for to authenticate?

Time to move ISP's

There are more than one way. That's not the only possibility.
Well given what I need and what is being offered by them, and of course how they manage the network, and my knowledge and all, changing ISP's is the next easiest choice.

If you can see a way around the authentication the ISP is doing, I'd be very interested to know.


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