hi,
i have a doubt regarding postfix mail server in RHEL-6.

There are 2 systems;
system1: server.example.com (postfix mail server)
system2: client.example.com (postfix installed)

Now, if the the postfix service is running on client.example.com,
then mail is being delivered to client system.

BUT when i stop the postfix service on client system,
no mails are coming on client system.

Now, i have a doubt if mail service has to be running on the client system to be able to get the mails ? What if the client doesn't have the mail packages installed ?
Isn't it possible to deliver the mail to the client if no mail related service is running on client system ?

FYI:
both system are able to lookup each other, selinux is disabled and iptables are flushed.

Thanks

Well if you want to deliver mail to a server then, yes, the mail server has to be running.