17 Sep 09 Linux – Exim, Avenger and SpamAssassin Tips

Further to Exim, MySQL, Courier IMAP, Courier POP3 & Spamassassin – vdomain and vuser set up, I’ve recently been receiving an increasing amount of spam, and have finally decided to take some positive action. Previously, my account would get hit with about 100 to 150 per day, of which 2 or 3 might get through. Lately, this has quickly increased to about 700+ of which at least 20 to 30 have been getting through, and I’ve been doing nothing but clearing spam day and night for the past few weeks. It is, however, critital that I do not catch any genuine email – I would rather keep on the side of caution and be more generous than not.
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Tags: avenger, courier, dcc, exim, IMAP, mail avenger, MySQL, POP3, spam, spamassassin

19 Oct 08 Exim, MySQL, Courier IMAP, Courier POP3 & Spamassassin – vdomain and vuser set up.

There’s a couple of guides out there on how to set up Exim, MySQL, Courier and Spamassassin in a virtual user environment but I thought I’d put together a high level basic guide myself.

My installation is running on debian etch 4.0 stable (2.6.18-6-686)

As this is a vdomain/vuser setup, you will not require a system shell/login for the users you add.

To start off, just install the packages you’ll need with apt-get:

Now if you already have exim4-* installed which is the default, you have two choices. We want to install our own exim version from source but without breaking the repository. The choices are to either just rename exim4 to exim4.old and then create your new exim install, or alternatively create a dummy empty exim4 package remove exim4-* and install your dummy package. This will resolve the dependancies issue in the package manager. Neither method is particularly clean – I have installed a dummy package personally and removed the real exim4 set of packages.
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Tags: courier, courier-authlib-mysql, courier-imap, courier-pop, courier-pop3, exim, exim4, make, make install, MySQL, source, spamassassin, spamc, spamd, tar, vdomain, vuser

14 Sep 08 Linux virtualization, vmware, xen, hosting, and squeezing the most out of your resources

I’d guess that 90% of hosting providers ‘oversell’. This essentially means that should they have 1,000GB allocated, they might offer 15 packages of 100Gb to 15 of their customers, banking on the fact that no one will fully use their 100GB allocation – Selling 5 Virtual Machines with 256MB RAM on a 1GB host, assuming that no one will use their full RAM allocation. This is bad, because you’ll generally be able to confirm that you’ve been allocated the resources, but nonetheless benchmark tests will show that you’re just not getting them, and your environment will be sluggish and unresponsive. This is the same as airlines selling 110 seats on a 100 seat plane. When that 101st paying customer does show up to claim his seat, he’s stuck without a flight.

The general consensus is that a VPS is a cheaper and lower-grade option than a dedicated service, however VPSs have a number of undisputable advantages over dedicated servers and I’m going to discuss why almost all the dedicated machines I manage are hosts for a range of VPSs.
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Tags: 10mbit, adamsinfo.com, advantages, allocation, apache2, backup service, benchmark, bind, cheap, client, co-locate, colocate, config, CPU, datacenter, debian, dedicated, dedicated servers, disk access, disk IO, endpoint, environment, exim, host, Hosting, hosting providers, Intel, kernel, kernel upgrade, mailserver, mppc, mppe, MySQL, named, noc, oversell, packages, php5, pptp, processor type, Quad Core, racks, reboot, remote services, routing, seek time, spamassassin, system administrator, tick speed, virtualization, vmware, vmware free server, vmware gsx, VPN, vps, xen, Xeon