SMTP Mail System Woes

Tarnus · **Joined:** Wed Feb 19, 2003 12:17 pm **Posts:** 2619

Well until you get that port 25 opened, you may not be able to send mail. SBC has a bad habit of doing that though.

Also alot of domains will try and reverse verify the user and the domain that is sending the mail to make sure it is valid.

iamsure · **Posted:** Fri Sep 16, 2005 5:57 pm

Zardoz wrote:

Called in today, they verified the change was made, checked everything over, promised it was open - still appears to be blocked.

But even from just telnetting to smtp.sbcglobal.yahoo.com 25, I can't get past the MAIL FROM: command.

Wait, which is it? Can you telnet and get a MAIL FROM: command, or is it blocked?

If you can get a response (MAIL FROM:), then the port itself is not blocked.

iamsure · **Posted:** Fri Sep 16, 2005 9:39 pm

Zardoz wrote:

When I speak of communicating using the MAIL FROM: (AUTH=) command, I am speaking to one of SBC's smtp servers. I can access that

EXCELLENT. Thats ideal.

Zardoz wrote:

and I was trying to use it as a relay server, but it wants authentication, which I have tried multiple times, and it just won't budge.

Are you using the right sequence?

First and foremost, for SMTP AUTH, you need to start with EHLO, not HELO. Second, you should use the AUTH in a seperate command, not in the MAIL FROM (the one in the mailfrom can be legally ignored).

Maybe this will help clarify: http://www.faqs.org/rfcs/rfc2554.html

Of course, this also assumes that one you get past all of this that the server is configured to relay for your address.. are you sure that is true?

iamsure · **Posted:** Sat Sep 17, 2005 11:48 am

Zardoz wrote:

[color=cyan]No, I am not sure that is true. Also, I'm using Postfix with SAS & TLS, the authentication is from a hashed password file, but I'm not sure whether Postfix is sending an EHLO or a HELO. The author's are pretty damned smart, so I would think it would be an EHLO, but I would need a packet sniffer (or the source code) to make sure. I guess it's not <i>that</i> important to me, but, again, it would be nice.

No, I meant when you test your interaction with SBC's smtp server. Thats the one you are telnetting to, and doing the HELO, and then MAIL FROM, yes?

Once you confirm that you can manually connect to SBC's smtp servers, do a EHLO, auth sequence, and mail from sequence, then you know their server will let yours do the same.

Then you can focus on your server.

Zardoz wrote:

So, I take it the AUTH should be on a command before the MAIL FROM, because once we get to that point, it kicks me.

Right. That url shows the sequence you should be testing with.

Zardoz wrote:

Still, theoretically, I should be able to telnet other mail servers on the internet at port 25, and at least see a firewall or something. That still bothers me.

Honestly, while its restrictive, its not 'wrong', exactly. In theory, you should always be using your ISP's smtp server to send out from them. The only time thats not true is if you are running a server with a dedicated connection, in which case you should have your own SMTP server that can send and receive.

From your description it sounds like your connection is more of a fast home connection than a dedicated circuit, so its par for the course.

SMTP Mail System Woes

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