postfix problem
 

Hello everybody, this is my first post so please bear with me.
My problem is when I recieve an email from someone the email will be delevered to me ok but the person mailing it to me will get a return message stating "This message was created automatically by mail delvery mail software. A message that you sent could not be delevered to one or more of it's recipients. This is a permanent error. The following addresses failed. mkeithm@localhost smtp error 550 mkeithm@localhost recipient address rejected user unknown at local recipient table.
Can anybody help me out on this?
Thanks
Michael Keith

First, welcome to LQ, mkeith.

About your question, please post the output of and the contents of your aliases file, the location of which is given by

here is my /etc/aliases file
 

root: mkeith
# Basic system aliases that MUST be present.
postmaster: root
mailer-daemon: postmaster
# amavis
virusalert: root
# General redirections for pseudo accounts in /etc/passwd.
administrator: root
daemon: root
lp: root
news: root
uucp: root
games: root
man: root
at: root
postgres: root
mdom: root
amanda: root
ftp: root
wwwrun: root
squid: root
msql: root
gnats: root
nobody: root
# "bin" used to be in /etc/passwd
bin: roott: mkeith
# Basic system aliases that MUST be present.
postmaster: root
mailer-daemon: postmaster
# amavis
virusalert: root
# General redirections for pseudo accounts in /etc/passwd.
administrator: root
daemon: root
lp: root
news: root
uucp: root
games: root
man: root
at: root
postgres: root
mdom: root
amanda: root
ftp: root
wwwrun: root
squid: root
msql: root
gnats: root
nobody: root
# "bin" used to be in /etc/passwd
bin: root
# Further well-known aliases for dns/news/ftp/mail/fax/web/gnats.
newsadm: news
newsadmin: news
usenet: news
ftpadm: ftp
ftpadmin: ftp
ftp-adm: ftp
ftp-admin: ftp
hostmaster: root
mail: postmaster
postman: postmaster
post_office: postmaster
# "abuse" is often used to fight against spam email
abuse: postmaster
spam: postmaster
faxadm: root
faxmaster: root
webmaster: root
gnats-admin: root
mailman: root
mailman-owner: mailman

# Further well-known aliases for dns/news/ftp/mail/fax/web/gnats.
newsadm: news
newsadmin: news
usenet: news
ftpadm: ftp
ftpadmin: ftp
ftp-adm: ftp
ftp-admin: ftp
hostmaster: root
mail: postmaster
postman: postmaster
post_office: postmaster
# "abuse" is often used to fight against spam email
abuse: postmaster
spam: postmaster
faxadm: root
faxmaster: root
webmaster: root
gnats-admin: root
mailman: root
mailman-owner: mailman

# /var/spool/mlmmj/myownlist (remember full path):
# myownlist: "| /usr/bin/mlmmj-recieve -L /var/spool/mlmmj/myownlist"
# Majordomo can be used to have mailinglists on your site.
#majordomo: "|/usr/lib/majordomo/wrapper majordomo"
#owner-majordomo: root,
#majordomo-owner: root,
# sample entry for a majordomo mailing-list called "test"
# read /usr/doc/packages/majordomo/README.linux for more information
# replace "test" with a new name and put the administrator into
# the "owner-test" alias instead of "root".
#
#test: "|/usr/lib/majordomo/wrapper resend -l test test-outgoing"
#test-outgoing: :include:/var/lib/majordomo/lists/test
#test-request: "|/usr/lib/majordomo/wrapper majordomo -l test"
#test-approval: owner-test,
#owner-test-outgoing: owner-test,
#owner-test-request: owner-test,
#owner-test: root,
#
# if you have bulk_mailer installed, you can replace the above
# "test-outgoing" line with the following:
#test-outgoing: "|/usr/bin/bulk_mailer owner-test@host.com /var/lib/majordomo/lists/test"

This syntax is wrong in the following two lines:
Did you cut and paste the file properly? You should use the "code" tags when you post to preserve the format.

Anyway, your error message (quoted below) indicates that mail is directed to mkeithm, a nonexistent user:

You're welcome. Scratch what I said about the majordomo line. It must have been too long in the browser I used before, so it wrapped around.