Sendmail problems


Some users of Asterisk systems have been complaining of emails not being delivered or defered.

IE getting

in the maillog.

This has been tracked down to certain ISPs who don’t support IPv6
to get round this problem add

to your

PBX in a Flash is affected by this issue as will most Sendmail 8.12 or later installations


A lot of mail servers will block your mail if you do not have a vaild MX record for your host name and many will blowck if your IP is in a range of an ISP. A good wrok around is relay your email through a mail relay such as

Many require that reverse DNS be setup also.


Err - that has NOTHING to do with sendmail!

Try looking in one of your other threads that you’ve posted on the same subject (as well as the pm you sent me!).

Sorry for being a ‘wannabe mod’ - but this sort of thing bugs the crap out of me.

simple solution:

yum -y remove sendmail
yum -y install postfix

nano /etc/postfix/

#change hostname and what ever you many think is needed

/etc/init.d/postfix restart

I noticed this problem awhile back and if you type


you will realise this issue should be taken seriously but just simply install postfix and all will be fine