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EMail Servers

Start / Stop / Restart Postfix Mail Server

How do I start / stop / restart my postfix mail server under Linux or UNIX operating systems?
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Linux Configure Sendmail as SMTP Mail Client ( submission MTA )

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?
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Postfix Forward Email To Another Email Account

I've multiple virtual domain hosted on CentOS Postfix server. How do I forward selected virtual domain email to yahoo / gmail or other email account using Postfix email server?
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Postfix Hide Client (MUA) System IP Address / Hostname

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?
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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[]: 554 5.7.1 Service unavailable; Client host [] blocked using xen.spamhaus.org; SPAMHAUS BLOCKLIST ADDRESS IS WRONG MUST FIX; from= to= proto=ESMTP helo=

How do I fix this problem?
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Postfix mail for domain.com loops back to myself Error and Solution

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?
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Postfix Backup MX eMail Server Anti-Spam Configuration

According to RFC2821 the lowest-numbered records are the most preferred MX for domain. So I've a target Postfix backup server to keep the messages in a queue waiting for the primary server to become available. This ensures that if my primary MX goes down I do not loss any emails. However, spammers are connecting to my backup MX to avoid anti spam filters that are running on the primary MX server. This also hides their real IP from my primary MX. How do I configure anti-spam for my backup RHEL / CentOS 5.3 based Postfix mx server?
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Postfix Configure Multiple ISP Client SMTP Authentication

How do I support multiple ISP accounts (smarthost) in the Postfix SMTP client for relaying email? For example:

[a] user1@isp1.com must be relay via smtp.isp1.com.
[b] user1@isp2.com must be relay via smtp.isp2.com.
[c] me@mycorp.com must relay all my default email via smtp.mycorp.com.
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Postfix Configure Client SMTP Authentication ( Smarthost Authentication )

My ISP requires that mail from my dynamic IP to our small business email addresses uses their outgoing SMTP servers. This is probably done to reduce abuse and spam but now I'm not able to send email and local Postfix log file displays authentication failure message. How do I relay mail through my mail ISP servers using Postfix SMTP under Linux / UNIX like operating systems?
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FreeBSD Install FuzzyOCR To Detect Image Spam

How do I install FuzzyOcr plugin for SpamAssassin to detect unsolicited bulk mail (Spam) containing images as the main content for Postfix mail server?
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