Posts Tagged ‘Firewall

Helping a colleague this week, we uncovered some odd behavior with a site whose performance he was analyzing. Upon first glance, it was clear that this site had a performance issue – they had HTTP persistence disabled. Immediate red flag in the areas of network overhead and geographic latency.
Further digging exposed something more sinister. It [...]

DNS hijacking is an occurrence that sends fear into the hearts of man and beast. It takes a perfectly harmless (yet critical) process and turns it into a weapon for chaos and mayhem.
This tool, however, does not simply reside in the hands of people looking to maliciously redirect traffic for purposes I can’t quite fathom [...]

I have had to disable the Digg measurements in GrabPERF as a number of the monitoring locations have been blocked by the Digg firewall.
Technorati tags: GrabPERF, Digg, digg.com, firewall

Just got MIDPSSH to work on my Razr. Had to perform a few hacks to get around the T-Mobile Firewall (SSHD now listens on port 110), but there is some perverse pleasure in seeing a linux command prompt on my Razr.
Maybe I need to do some real work now.
Technorati Tags: Razr, SSH, MIDPSSH, T-mobile

As part of the work I am doing for a client, I needed to install the Check Point VPN software. So far so good.
Until I want to try and connect to my company’s VPN, which uses Netscreen. It didn’t work.
Seems that the Check Point software does something that I both agree with and find frustrating [...]

Well, due to the paranoid 1d10ts who run my work network, I can’t test the remote script from my work linux machine. I have one beta tester and need some others to ensure that it works.
Again, what you need on your linux machine:

cURL (compiled from source or with the devel packages)
MySQL client and devel packages
Time::CTime [...]

Traffic Shaping with tc

In: smp

6 Jul 2005

I have discovered a little secret of Linux today: tc. The Linux Advanced Routing & Traffic Control project (here) allows you to shape traffic in any way that you want. In most cases, it is used in a situation where a multi-homed Linux box is used as firewall/router.
I have activated it on my Web server, [...]

Some great unsolicited positive feedback on the services my employer provides. [here]
Would love to answer any questions the author has about some of the inside-the-firewall services we provide.
Technorati: Gomez Performance Network, Web Performance Measurement, Web Performance Monitoring, Web Performance, HTTP

ZoneAlarm Borked…Again!

In: smp

28 Jun 2005

I hate running Windows.
I hate that the firewall app that I have run for years has suddenly decided to go and melt down into a giant puddle of goo, taking the CPU with it.
About two weeks ago, ZoneLabs released a broken update for their ZoneAlarm product.
Whoops! I did it again!
Yesterday, my Dell laptop slowed to [...]

Seems that some firewalls with Content Filters are brain-dead. I found another firewall that provides the same anti-compression “service” for its customers. [here]
Thanks to Alexy Titov for the link.


About this blog

Stephen Pierzchala is one of a 10-year veteran of the Web performance field who also writes on topics that interest his non-linear world-view.

Contact

stephen@pierzchala.com

+1 (508) 410-3865