mail

Thunderbird is a great choice for a mail client on Linux systems if you prefer a GUI, but I had some problems with fonts in the most recent releases.

When I started Thunderbird today, it opened three windows.

I’ve been a big fan of Thunderbird for years, but it lacks features in some critical areas.

I talked about the joys of running my own mail server last week only to find that my mail server was broken yesterday.

I’ve received some very sophisticated phishing emails lately and I was showing some of them to my coworkers.

I’m in the process of moving back to a postfix/dovecot setup for hosting my own mail and I wanted a way to remove the more sensitive email headers that are normally generated when I send mail.

If you want to forward e-mail from root to another user, you can usually place a .

Occasionally, I’ll end up with a mailbox full of random data, alerts, or other useless things.

If you have a Plesk server where short mail names are enabled, upgrading to Plesk 8.

Normally, qmail will be able to process the mail queue without any interaction from the system administrator, however, if you want to force it to process everything that is in the queue right now, you can do so:

If you’re working in Plesk and you receive this error:

On a Plesk server, the maximum size for an individual e-mail sent through qmail is unlimited.

I really dislike qmail.

If you see a large mail queue and your system’s I/O is increasing, you may find messages like these in your syslog:

One of my biggest complaints on RHEL 4 is the large resource usage by the version of SpamAssassin that is installed.

If you have a new Plesk installation and the following option is greyed out in Server -> Mail:

I stumbled upon this peculiar bounce message recently while working on a server:

You may catch this error when you attempt to start dovecot on a Red Hat Enterprise Linux 5.

If you’ve used newer versions of Horde with Plesk, you have probably noticed the news feed that runs down the left side of the screen.

I stumbled upon a server running Plesk 8.

One of my biggest beefs with Plesk’s e-mail handling is the lack of server-side filtering.

A few days ago, I stumbled upon a server running qmail with qmail-scanner.

If you’re using Plesk 8.

In some situations with dovecot running on your server, you may receive a message from your e-mail client stating that the “connection was interrupted with your mail server” or the “login process failed”.

On brand new Plesk 8.

I’ve seen quite a few situations where the Horde login process can take upwards of 45 minutes to log a user into the webmail interface.

Since AOL sends their users’ traffic through proxy servers, this can cause problems with Horde’s session handling in Plesk.

If you want to adjust how long postfix will hold a piece of undeliverable mail in its queue, just adjust bounce_queue_lifetime.

If you have SpamAssassin installed, but you want to make sure that it is marking or filtering your e-mails, simply send an e-mail which contains the special line provided here:

By default, Red Hat Enterprise Linux 2.

So, this is not really related to the normal system administration topics discussed here, but it’s Sunday, so I feel like something different.

Let’s say you have a user who can’t receive e-mail.

If you find yourself in a pinch and you need a temporary fix when your primary IP is blacklisted, use the following iptables rule:

When connecting to your server’s POP3 service, your client might provide this error just after authentication:

It’s not abnormal for qmail act oddly at times with Plesk, and sometimes it can use 100% of the CPU.

If you have to use short e-mail usernames in Plesk (which is a bad idea), and someone accidentally sets the server to use full usernames, you can force Plesk to go back.

Enabling submission port support for Postfix is really easy.

Depending on your situation, it may be handy to redirect e-mails that have a certain subject line before it even reaches a user’s inbox.

If you have postfix installed with OpenSSL support compiled in, you can enable SSL connections by editing two configuration files.

If you want to adjust how long e-mails will spend in the qmail queue before they’re bounced, simple set the queuelifetime:

By default, sendmail will keep items in the queue for up to 5 days.

Should you find yourself needing to send e-mail destined for a certain account to a blackhole or to /dev/null, you’ll find very little information from Google.

Normally, Postfix will reject e-mail sent to non-existent users if a catchall isn’t present for the specific domain that is receiving mail.

To enable submission access on port 587 in sendmail, add the following to the sendmail.

If you’re checking through your mail logs, or you catch a bounced e-mail with “554 relay access denied” in the bounce, the issue can be related to a few different things:

If you can’t send mail via port 25 due to blocks imposed by your ISP, you can enable the submission port within Plesk pretty easily.

If you find that Horde (with Plesk) keeps refreshing when you attempt to log in, and there are no errors logged on the screen or in Apache’s logs, check the session.

If you find yourself in the situation where you need to bulk add SPF records to every domain in Plesk, you can use this huge one-liner:

If you ever need to communicate with a POP3 server via telnet to test it, here’s some commands you can use:

To disable reverse lookups in qmail with Plesk, simply add -Rt0 to the server_args line in /etc/xinetd.

This is one of Exim’s more cryptic errors:

If you need to change the hostname that Sendmail announces itself as, just add the following to sendmail.

Often times, the wonderful webmail application known as Horde will spin out of control and cause unnecessary resource usage and often cause defunct Apache processes to appear.

I rarely try to toot my own horn, but I’ve created a pretty handy site.

To stop those evil double bounce e-mails in Plesk, just do:

You can edit /etc/drweb/drweb_qmail.

If odd bounced e-mails are coming back to the server or the server is listed in a blacklist, some accounts may be compromised on the server.

If you’re looking to get PCI/CISP compliance, or you just like better security, disable SSL version 2.

There’s three main things to remember when it comes to the qmail queue:

If you find yourself in the sticky situation where kill -9 still won’t kill a sendmail process, check the process list.

If your server is spewing an invalid HELO, you could be blacklisted pretty quickly.

Setting up Postfix to handle mail for a virtual domain and forward it to external mailboxes is pretty easy.