Archive for May, 2005

PF’s skip on interface directive

The OpenBSD packet filter (PF) received several enhancements in OpenBSD 3.7. One of the coolest things is the ability to tell PF not to filter traffic on specific interfaces, such as the loopback interface. This behavior is defined in the pf.conf configuration file with the “set skip on” statement: set skip on lo0 Prior to […]

Fix for Solaris SSH client hangs

One of my colleagues came to me with an ssh problem a few weeks back, and I thought I would share my findings here. The issue centered around ssh hanging when you tried to invoke a command on a remote server, similar to this: $ ssh host “ls -la” When I added the “-vv” (verbose […]

Using automator to convert text to audio

While reading the latest tips on Mac OS X hints, I came across a cool tip on using Tiger’s automator to convert text documents to audio. I am trying to read through RFC 2616, and thought this would be a perfect document to listen to while walking to class. Once you open automator, you need […]

Filtering attachments with procmail

I have been performing some basic statistical analysis on the spam and viruses I receive, and it seems like more and more Email comes littered with silly attachments. While I really appreciate people sending me executables, help files, compressed archives, VB script and screen savers, I should alert you now that these messages go directly […]

Contract law

It is amazing how many processes and transactions are governed by contract law. Real estate sales contracts, credit card applications, bills of sale, apartment leases, land contracts, mortgages (or deeds to secured debt if you live in Georgia), and deeds are all governed by contract law, which is quite complicated. While reviewing a sales contract […]

Generating random numbers

Randomness is a key element in cryptography (seeds and shared secrets), TCP (ISNs), and can be useful when simulating client access patterns in test scripts. If an OS supports the /dev/random pseudo-device, the dd, od, and awk utiltiies can be used to generate random values: $ dd if=/dev/random count=1 2>/dev/null | od -t u1 | […]

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