Mailinglist Archive: opensuse (5130 mails)

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Re: [SLE] SMTP authentication
  • From: "Hylton Conacher (ZR1HPC)" <hylton@xxxxxxxxxxxx>
  • Date: Mon, 01 May 2006 17:45:08 +0200
  • Message-id: <44562D04.5050303@xxxxxxxxxxxx>
Carlos E. R. wrote:

The Saturday 2006-04-29 at 13:57 +0200, Hylton Conacher (ZR1HPC) wrote:


Sandy, the above paragraphs were pivotal to my understanding. Free beer/fruit
juice on the house for Sandy.

I have saved that email ;-)
I have a feeling it could be used against me :)

So eventhough my local SMTP server dials up to the internet with a certain
username and password, that same username and password would not be used as
authentication between my local SMTP server and the ISP's one, should it be
used as a relay?

No, your postfix uses the file "/etc/postfix/sasl_passwd" to decide what login/passwd to use. It contains lines like this:

mailhost.your.isp loginame:password

it means that, when talking to smtp server at "mailhost.your.isp", it must use the login/pass pair to the right. ISPs normally use the same password for everything (login, pop3, smtp, ftp...) just to save work.
So provided the sasl login/password are correct the receiving SMTP server doesn't care what the details are in the FROM header? (The reeing SMTP server would not do authentication if it is the destination SMTP server).

Notice that if we had several users with accounts at that site, we would have problems... it is a server side configuration, not a users' configuration.
I don't understand why it would be a problem. If the SMTP server os configured with a certain SASL username/password, surely it doesn't matter which user sends mail to server (A)? Server A will connect at predetermined times to send its waiting mail and each user will not be able to force A to send if it is not connected.

Hylton Carlos Sandy Patrick
| | | |
(B) Relay SMTP server
(C) Destination SMTP server

The easiest way to test it is to set up several mail accounts in your
mailclient and configure each account to send with the same user/pass to
your ISP mailserver.

Sorry, I didn't see that I was able to specify the name and password the new
SMTP server I had added. :()

Mozilla will ask for the login/pass with a dialog at the moment it connects and sees they are needed.
OK, that is what I thought.

I've added a new entry for and used my gmail username to
authenticate. It didn't request a password so I assume that will come up when
I send the message.

I'm an IDIOT!! I forgot about the port number.

Thanks for the gmail settings. I will make mine so.

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