Linux under the PHP mail or sendmail send mail slow solution

Mail slow and timeout is due to sendmail slow, but sendmail slow and how to solve it?

The first step: Of course, check the log:

Vim/var/log/maillog

June 5 23:26:20 localhost sendmail[1206]: My unqualified host name (localhost) unknown; Sleeping for retry
June 5 23:27:20 localhost sendmail[1206]: Unable to qualify I own domain name (localhost)--Using short name
June 5 23:27:20 localhost sendmail[1206]: r65frkmm001206:from=nobody, size=187, Class=0, Nrcpts=1, msgid=<20130705152 7.r65frkmm001206@localhost> a relay=nobody@localhost.
June 5 23:27:20 localhost sendmail[1207]: r65frkba001207:from=<nobody@localhost>, size=398, Class=0, Nrcpts=1, MSG Id=<201307051527.r65frkmm001206@localhost&gt, PROTO=ESMTP, Daemon=mta, Relay=localhost [127.0.0.1]
June 5 23:27:20 localhost sendmail[1206]: r65frkmm001206:to=aaa@gmail.com, Ctladdr=nobody (99/99), delay=00:00:00, Xdela y=00:00:00, Mailer=relay, pri=30187, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=sent (r65frkba001207 message Accepted for delivery)
June 5 23:27:22 localhost sendmail[1209]: starttls=client, relay=gmail-smtp-in.l.google.com, Version=tlsv1/sslv3, Verify=fail, Cipher=rc4-sha, bits=128/128
June 5 23:27:25 localhost sendmail[1209]: r65frkba001207:to=<aaa@gmail.com>, ctladdr=<nobody@localhost> ( 99/99), delay=00:00:05, xdelay=00:00:05, MAILER=ESMTP, pri=120398, relay=gmail-smtp-in.l.google.com. [74.125.129.26], dsn=2.0.0, stat=sent (OK 1373038045 qn3si5112247pbc.62-gsmtp)
June 5 23:30:01 localhost sendmail[1212]: My unqualified host name (localhost) unknown; Sleeping for retry

Step two: Add a domain name to the hosts table

#hostname

Vim/etc/hosts

Add as follows

:: 1 localhost localhost.localdomain localhost6 localhost6.localdomain6 your domain name

If it doesn't work out the way it is,

Check that the php.ini settings are correct
Cat/etc/php.ini | grep Sendmail_path
The right result should be something like this.
Sendmail_path = Sendmail-t-I.

Check if the SendMail is installed
Which SendMail
Normal results should look like this.
/usr/sbin/sendmail

If the path above does not find SendMail
Check to see if the package is installed
Yum List Installed | grep sendmail