application availability monitoring

The availability of any enterprise application is only as good as the monitoring solutions utilized. The reason being that a well thought out / well deployed monitoring solution not only detects when an application has failed to respond to requests, it can also take steps to being remedy the problem without involving human intervention. The last thing any admin wants to be waken up at 3a only to hit the restart button for the downed service. (more…)

packet capture repository

Ever asked yourself the question of “I wonder what a trace of my favorite application protocol looks like”? I did that today and found myself browsing through the collection of sample packet captures on wireshark.org. The collection is quite impressive. There are nearly 50 categories of packet captures available, from HTTP to NTP to SQL to IPSec to Kerberos. You can even check out a capture of a slammer worm! Anyway, I thought this is a great resource and want to pass it on.

Linux Files System Encryption

Encryption of files on a server is often the last gate in keeping unauthorized users from gaining access to sensitive data. File-level encryption is prevalent with tools like PGP. Unfortunately file-level encryption still exposes the OS structure of a server to the hacker. Plus, managing the encryption/decryption of individual files can be expense from a system resource perspective. An alternative would be to encrypt the entire file system and perform the encryption/decryption at the file system level on the fly. (more…)

Load Balancing Email

Here’s a different approach on using DNS to distribute users across multiple email servers. Load Balancing Email

DNS design 101

A little dated but has a good background on DNS design. This is a must-know for anyone that deals with delivery of applications.

Domain Name System Design Considerations