Sendmail Error : NOQUEUE: SYSERR(root): No local mailer defined NOQUEUE: SYSERR(root): QueueDirectory (Q) option must be set

Error using m4 macro while building sendmail.cf from sendmail.mc on RHEL 6 / CentOS 6 flavors?

[root@cent1]# m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf

m4:/etc/mail/sendmail.mc:10: cannot open `/usr/share/sendmail-cf/m4/cf.m4': No such file or directory

[root@cent1]#

The above error is because the package sendmail-cf is not installed.

You will have the below error messages on the /var/log/maillog file also. 

sendmail[3215]: gethostbyaddr(10.0.3.15) failed: 2

sendmail[3215]: NOQUEUE: SYSERR(root): No local mailer defined

sendmail[3215]: NOQUEUE: SYSERR(root): QueueDirectory (Q) option must be set

The above error is because the sendmail.cf is not configured properly. 

Fix is to install the package sendmail-cf, build sendmail.cf from sendmail.mc and restart sendmail service.

Install the sendmail-cf

# yum install -y sendmail-cf

Comment the entry which makes the sendmail listens only to loopback address as below by adding "dnl" on /etc/mail/sendmail.mc

# vi /etc/mail/sendmail.mc

dnl # DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl

# m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf

# service sendmail restart

Check if sendmail is started properly.

[root@cent1 ~]# netstat -tulnp |  grep -i :25

tcp        0      0 0.0.0.0:25                  0.0.0.0:*                   LISTEN      3748/sendmail

[root@cent1 ~]#

Hope this helps.

Jk