Linux Configure Sendmail as SMTP Mail Client ( submission MTA )

Posted on in Categories , , , , , , , , , , last updated July 24, 2009

I‘ve central e-mail server. Other servers does not need to operate as a mail server. How do I configure Sendmail as submission-only e-mail server (mail client) under CentOS / Fedora / RHEL / Debian Linux / UNIX like operating systems?

Postfix Hide Client (MUA) System IP Address / Hostname

Posted on in Categories , , , , , , , , , last updated June 17, 2009

I‘ve central mail server gateway. All of our internal systems through this box. How do I remove or hide the hostnames and IP addresses of our internal systems from the messages headers before they go out to other users for security purpose?

SPAMHAUS BLOCKLIST ADDRESS IS WRONG MUST FIX Error and Solution

Posted on in Categories , , , , , last updated May 7, 2009

I‘ve configured RBL for my postfix based mail server and I’m getting an error that read as follows:

May 3 04:35:37 mx02 postfix/smtpd[10956]: NOQUEUE: reject: RCPT from ant251.neoplus.adsl.tpnet.pl[83.26.101.251]: 554 5.7.1 Service unavailable; Client host [83.26.101.251] blocked using xen.spamhaus.org; SPAMHAUS BLOCKLIST ADDRESS IS WRONG MUST FIX; from= to= proto=ESMTP helo=

How do I fix this problem?

Postfix mail for domain.com loops back to myself Error and Solution

Posted on in Categories , , , , , , , , last updated June 2, 2009

I can send and receive mail using user@example.com, but system generated emails such as root@mail.example.com bounce backup with an error:

May 1 03:14:52 mail postfix/smtp[62798]: 23CA4BD6B40: to=, relay=none, delay=0.01, delays=0/0/0/0, dsn=5.4.6, status=bounced (mail for mail.example.com loops back to myself)

How do I fix this error?