Sometimes it becomes necessary to masquerade the domain name of the sender .At my work place there was a rule set in the exchange server  which blocks mails to my mail ids which are  coming from domains other than desireddomain.com .Even if  I want to test the sendmail functionality in our solaris servers I can't verify it by sending to my mail id.Here masquerading helped me.Please see the configuration i used.

Let the domain name be 123.com in /etc/hosts file.

1.Edit sendmail.mc file

   Enter masquerading feature just before the MAILER section.

# vi /etc/mail/sendmail.mc

define(`confFALLBACK_SMARTHOST', `mailhost$?m.$m$.')dnl

FEATURE(masquerade_entire_domain)

FEATURE(masquerade_envelope)

MASQUERADE_AS(`desireddomain.com')

MASQUERADE_DOMAIN(`123.com')

MAILER(`local')dnl

MAILER(`smtp')dnl

2.Create the sendmail.cf file

# cd /etc/mail

# /usr/ccs/bin/make sendmail.cf

3.Reread the configuration file.

Send the Sendmail process a SIGHUP to begin using the new configuration file.

kill -HUP `head -1 /var/run/sendmail.pid`

or

Restart the sendmail service

# svcadm restart sendmail

4.Testing the configuration

Login as a user other than root(root user is an Exposed user pls don't masquerade him)

Let the user be suresh and domain be 123.com.The sender will be displayed as suresh@desireddomain.com to user@xyz.com,the recipient of the mail.

$ mailx -v -s "test" user@xyz.com

hi

.

Observe the output we can see  suresh@desireddomain.com as sender address instead of suresh@123.com.


As sendmail is not depending on any particular OS it should be applicable in other Operating systems also.

Here the exchange server rule got bypassed...

Great You have done !!!