Archive for July, 2008

Reducing Memory Used by Milter-Greylist

Monday, July 21st, 2008

Our VPS was running low on free memory the last few weeks.  After a bit of research, we realized that our email greylisting software, Milter-Greylist was using the most memory of everything installed on our server.  More than our database engine, web server, email server, and everything else (not combined)!

For those who don’t know, Grey Listing delays emails in an attempt to foil spammers which don’t typically follow standards for retrying email messages. Milter-greylist is a package that works with sendmail, our SMTP server. Milter-greylist is great, however, it keeps it’s working history in memory, which was OK for the two years that we have run it.  However, the amount of spam attempts continues to rise… why don’t home users notice that their computers have become SPAM zombies anyway?

So, the milter-greylist was storing tens of thousands of records in memory.  It had to be reduced.  Rather than switch to a database driven greylisting package, we decided to start blocking some SPAM attempts earlier in the process.

We enabled the outright blocking of inbound email attempts by any IP address listed on’s SBL+XBL list.  SBL+XBL are lists of computers (built by crazy wizardry) that one can use to blacklist email attempts.  I’m uncomfortable using blacklists like this, but, what can you do?  The odds of good mail being lost are very small, and hopefully, anyone who happens to get bounced unintentionally can phone us.

So, following the simple instructions here:

We were able to reduce the traffic to Milter-Greylist and it’s memory usage by 2/3 to 3/4!  Uptime and performance of our VPS and therefore everything hosted on it should be slightly better.

Spammers suck.

A new blog we’re hosting: “You’re not sushi – you’re Chicken!”

Monday, July 21st, 2008

Perceptus hosts a few sites for friends, family, and other non-commercial purposes.

We added a new one a few days ago for Leonard, his sister, and a couple of their cousins. This crazy subset of the Chan Clan is up to no good again.*

They are building a giant roast chicken on wheels and it’ll be screaming down the first Red Bull Soapbox Race in Canada, this September 7, 2008 in Vancouver.

So, check out the You’re not sushi – you’re Chicken! in Red Bull Soapbox Vancouver 2008 blog.

* They were part of the Red Bull Flugtag Vancouver 2006, with the amazingly large and beautiful craft, The Wild Sushi – this blog is also hosted by Perceptus Solutions Inc.

I hate banning IP addresses…

Sunday, July 6th, 2008

Today I noticed that one IP address has been using wget, a command line tool for grabbing web pages, to get random words from’s random word fetcher about once per second.  I’m not sure how long this has been going on, but I have stopped it today.

The way to ban an IP address on a single website on an Apache web server turned out to be easier than I expected.  Just edit .htaccess and add two lines similar to this:

# banned IPs
deny from

Actually, the line starting with a # sign is optional, that’s a comment in the .htaccess.

That’s it.

As for who was trying to use the Naque for Unique Names nefariously?  I’m not sure who it was, or what was the purpose.  Whoever it is, if you read this, and if it was for something reasonably worthwhile (i.e. not SPAM), then drop me a line and ask for permission.  Until then, you’re banned from the site.

Summer Break Bingo

Thursday, July 3rd, 2008

We meant to get this new word list ready about 2 weeks ago, but somebody spent a bit too much time enjoying the sun to finish on time… :)

We have a new word list for the end of the school year.  So, create and customize your bingo cards, by visiting and opening our template word list for the Last Day of School bingo game.

As always, the basic use of the site is free.  You can currently unlock our Premium features for only $10.

Have fun in the sun!
Let’s see if we can get a Fourth of July word list done before midnight, shall we?