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Mail Server Relay Authentication Failure in Server Admin

I need to set up Mail Server to relay through my ISP. I know that I can authenticate to smtp.comcast.net:587 using my account and TLS usnig a mail client.


However, when I use Server Admin to configure my server's SMTP to send all outgoing email through this relay (Server Admin>Mail>Settings>General>


Rely outgoing mail through host: smtp.comcast.net:587

Authenticate to rely with user name: user


I get the SMTP error:


SASL authentication failed: cannot authenticate to server smtp.comcast.net[76.96.62.117]: no mechanism available


There are no toggles on Server Admin to specify TLS or SSL or anything for authentication.


Does anyone know how to tell Server Admin how to authenticate an SMTP relay to smtp.comcast.net using TLS, which is apparently what comcast expects?

Mac mini, Mac OS X (10.6.7)

Posted on Apr 25, 2011 9:07 AM

Reply
Question marked as Top-ranking reply

Posted on Apr 25, 2011 9:44 AM

Wow, this is an obscure solution, but it works. According to this thread, the problem is that:


Although Comcast advertises "AUTH LOGIN PLAIN", the Postfix SASL library won't do plain text auth by default. It needs to be told it's okay with:


smtp_sasl_security_options = noanonymous


Solution:


$ su -

$ cd /etc/postfix

$ cp main.cf main.cf.no_smtp_sasl_security_options

$ echo 'smtp_sasl_security_options = noanonymous' >> ./main.cf

$ serveradmin stop mail

$ serveradmin start mail


I'm not sure how often /etc/postfix/main.cf is overwritten, but presumably this happens every time you change and save Mail settings in Server Admin, so you must redo these steps every time you change the Mail server if you want to use smtp.comcast.net as your mail relay.


AAPL, would you please add a toggle to handle this in Server Admin?

6 replies
Question marked as Top-ranking reply

Apr 25, 2011 9:44 AM in response to realzcubed

Wow, this is an obscure solution, but it works. According to this thread, the problem is that:


Although Comcast advertises "AUTH LOGIN PLAIN", the Postfix SASL library won't do plain text auth by default. It needs to be told it's okay with:


smtp_sasl_security_options = noanonymous


Solution:


$ su -

$ cd /etc/postfix

$ cp main.cf main.cf.no_smtp_sasl_security_options

$ echo 'smtp_sasl_security_options = noanonymous' >> ./main.cf

$ serveradmin stop mail

$ serveradmin start mail


I'm not sure how often /etc/postfix/main.cf is overwritten, but presumably this happens every time you change and save Mail settings in Server Admin, so you must redo these steps every time you change the Mail server if you want to use smtp.comcast.net as your mail relay.


AAPL, would you please add a toggle to handle this in Server Admin?

Sep 25, 2011 11:23 AM in response to realzcubed

Hi


I'm trying to setup the mail relay for my mail server (Lion Server / Postfix).

I added the smtp_sasl_security_options = noanonymous parameter in the main.cf, reloaded the postfix config and I still get the "

SASL authentication failed; cannot authenticate to server relay.dnsexit.com[64.182.102.186]: no mechanism available" error.


I use port 26 to relay as my provider is blocking the 25.


Any help would be greatly appreciated.

F.

Jul 1, 2013 10:45 AM in response to realzcubed

Just in case this helps anyone, the following worked for me with a similar relay (smart host) problem when Rackspace ended support for CRAM-MD5:


sudo serveradmin set mail:postfix:smtp_sasl_security_options = "noanonymous"


You may want to make sure you're using SSL too but that was not an issue for us.


The changes made through the serveradmin command line utility appear to survive saved changes in the Server Admin app.

Mail Server Relay Authentication Failure in Server Admin

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