Problem when send mail from outlook

[himoi]

Hello all,
I setup a mail server for our company, i used "Released 5.0.5_GA_2201.RHEL4_2008041732 CentOS4 FOSS edition"
mail server is behind the Nat firewall and i publish my email to internet.
My problem is I can get mail and send mail from LAN network by MS outlook 2003, but when I go to business, I can not send email from MS Outlook.
I checked /var/log/zimbra.log file on my email server, It report that
"Jul 22 08:11:11 hcmcexch2 postfix/smtpd[27500]: NOQUEUE: reject: RCPT from unknown[220.231.82.132]: 450 4.7.1 Client host rejected: cannot find your hostname, [220.231.82.132]; from=<vinhhv@atvn.com.vn> to=<vinhhv@atvn.com.vn> proto=ESMTP helo=<mypc>
Jul 22 08:11:16 hcmcexch2 postfix/smtpd[27500]: disconnect from unknown[220.231.82.132]"

Please tell me how i can fix this problem
Thank you

[uxbod]

On your server please perform the following and post back the results

su - zimbra
zmprov gacf | grep zimbraMtaRestriction

this will show what AntiSPAM measures are in place.

[himoi]

This is result:
[root@hcmcexch2 ~]# su - zimbra
[zimbra@hcmcexch2 ~]$ zmprov gacf | grep zimbraMtaRestriction
zimbraMtaRestriction: reject_invalid_hostname
zimbraMtaRestriction: reject_non-fqdn_hostname
zimbraMtaRestriction: reject_non_fqdn_sender
zimbraMtaRestriction: reject_unknown_client
zimbraMtaRestriction: reject_unknown_hostname
zimbraMtaRestriction: reject_unknown_sender_domain
zimbraMtaRestriction: reject_rbl_client dnsbl.njabl.org
zimbraMtaRestriction: reject_rbl_client cbl.abuseat.org
zimbraMtaRestriction: reject_rbl_client bl.spamcop.net
zimbraMtaRestriction: reject_rbl_client dnsbl.sorbs.net
zimbraMtaRestriction: reject_rbl_client sbl.spamhaus.org
zimbraMtaRestriction: reject_rbl_client relays.mail-abuse.org

[uxbod]

Well the reason why your emails are being rejected is due to the MTA restriction reject_unknown_hostname. If you were to disable this it would allow your emails to be sent, but would also mean that any internet emails would also bypass this check which is not good. You need to assign a hostname to your machine and ensure that it is resolvable by your ZCS server.

[himoi]

hello,
I don't understand your ideas, you see that my machine still have a host-name (mypc - as you see in log file that i give you).
In our zimbra, why i can not using smtp authencation to do this?
Ex: log in before send mail authentication that i see in outlook setting
Vinh

[himoi]

Anybody can help me? :-(

[himoi]

Please help me, I need to solve this problem, because i can not send mail when i go business with my laptop