HELO.
 when i say......
 MAIL FROM:someone@some.other.domain
 ....it responds that the sender's address should resolve.....what
 does that mean???
 i thought because it sends mail ......it should accept all sender
 addresses!!!
 At the same time.....if i say
 MAIL FROM:some_other_login_on_my_linuxbox@localhost
 the mail is sent....even if "some_other_login_on_my_linuxbox" knows
 nothing about it!!!

When you give MAIL FROM: someone@some.other.domain, the domain some.other.domain should be resolved by your local DNS or the DNS of your ISP. When you use some_other_login_on_my_linuxbox@localhost, sendmail knows that its a valid domain.

Regards, Mayur Joshi

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