hi,

i used yum install postfix,
but i don't know it's support sasl ?
how to check it?

Don't know, since you provide no real details, tell us version/distro of Linux, what you've done, etc.

Did you try to look this up on Google????
http://www.linuxhelp.net/forums/lofi...php/t3647.html

problem:
the postfix & saslauthd are running.

[root@mail ~]# telnet 172.16.0.5 25
Trying 172.16.0.5...
Connected to mail.ljing.dom (172.16.0.5).
Escape character is '^]'.
ehlo
--------------> nothing && ctrl+c can't exit.



[root@mail ~]# rpm -q postfix
postfix-2.3.3-2.1.el5_2
[root@mail ~]# rpm -q cyrus-sasl
cyrus-sasl-2.1.22-5.el5_4.3
[root@mail ~]# uname -a
Linux mail 2.6.18-194.el5 #1 SMP Fri Apr 2 14:58:35 EDT 2010 i686 i686 i386 GNU/Linux

append flowing agars in main.cf

smtpd_sasl_auth_enable = yes
smtpd_sasl_local_domain = $myhostname
smtpd_recipient_restrictions = permit_sasl_authenticated permit_auth_destination reject
broken_sasl_auth_clients = yes
smtpd_sasl_security_options = noanonymous




tail /var/log/messages
Aug 18 04:16:50 mail saslauthd[31543]: main : no authentication mechanism specified
Aug 18 04:17:12 mail saslauthd[31544]: main : no authentication mechanism specified
Aug 18 04:17:40 mail saslauthd[31550]: detach_tty : master pid is: 31550
Aug 18 04:17:40 mail saslauthd[31550]: ipc_init : listening on socket: /var/run/saslauthd/mux

Why, exactly, is that a problem??

Your first post wanted to know if SASL was supported. Obviously, it not only IS, but it's already installed and running. You were also asked for details, such as version/distro of Linux, etc., but still haven't provided them. If you don't want to answer questions that help us to help you, not much point in posting....