We picked up a Watchguard Firebox FB-10R from RE-PC (Tukwila) for 15 bucks. There is almost always some kind of auction on Ebay selling a Firebox FB-10. The motherboard on ours, it turns out, was damaged. Now the Firebox FB-10R is just a regular PC clone. It has three 3COM 3C509 NICs in it. We […]
Recycling a Watchguard Firebox FB10
Installing a TFTP Server on Red Hat 8.0
In this story we showed how to upgrade IOS on a Cisco using a TFTP server available from Cisco that ran on Windows. Well, just suppose you wanted to load a new IOS image from a TFTP server on a GNU/Linux box. We will use Red Hat 8.0 to provide a TFTP server. First, install […]
Firewall on a Floppy
Check out floppyfw for a simple firewall and IP sharing device. No hard drive is needed, and 16 megs of RAM is more than enough. The instructions on the site and in the comments in the config files are quite easy to follow. One somewhat tricky problem is if you are using a network card […]
Some Useful RFCs
HTTP: RFC 2068 POP3: RFC 1725 SMTP: RFC 821 FTP: RFC 959
Installing Network Probe
Network Probe is a free network monitor and protocol analyzer that runs on Windows NT/2K/XP, Linux, FreeBSD, Solaris (Intel), and Mac OS X. We downloaded the Linux version by filling out the form here. The form wasn’t too intrusive, and the email with the download information came back quickly. We used version 0.4 for this […]
Setting Up Network Load Balancing on Windows 2000 Advanced Server
Network load balancing is a service that comes with Windows 2000 Advanced Server (not plain old Windows 2000). In this article we will set up Network Load Balancing on a cluster of two systems and test via the telnet service. The Network Load Balancing service is unlike other popular load balancing schemes like Red Hat […]
Using the WLBS CLI tool to Control Network Load Balancing on Windows 2000 Advanced Server
In order to use the WLBS CLI, you need to enable remote control: The WLBS CLI lives as wlbs.exe in system32. Query the cluster: C:\>wlbs query 10.50.100.10 /passw WLBS Cluster Control Utility V2.3. (c) 1997-99 Microsoft Corporation Password: Accessing cluster ‘10.50.100.10’ (10.50.100.40): Host 7 (10.50.100.17) reported: converged Host 1 (10.50.100.11) reported: converged as DEFAULT Host […]
Initial MRTG Configuration
MRTG is a monitoring tool for traffic loads on network-links. It will create HTML pages with visual representation of both the current and historical load on the device. The server we will use for this article is the Gentoo box we built in this article. With Gentoo, we simply run emerge and a bunch of […]
Creating a PPP Connection to a Cisco Aux Port
In this article, we set up MRTG to monitor an old Cisco 1720 router. Now, it is nice to have *two* interfaces on a lab router so that you can route between two physical interfaces. We tried adding a second FastEthernet module instead of the T1 module we have, but the firmware was too old. […]
Using the Ping -f Option to Test for Lost Packets
There is a cool option on some versions of ping. With the -f option, a dot is printed for each ping sent, and a backspace is printed when a ping is received. This gives you an instant visualization of the lost packets. Hit ctrl-c to end the task, and you will then see the latency […]
AreWeDown Trace/Latency Tool
We wrote up a tool that will generate a latency and trace report based on your IP address. Note that this is the IP address that the web server detects your client has. First it pings your IP address with 50 pings or 5 seconds worth of pings, whatever is the most restrictive. If 50 […]
Solving Network Congestion Issues With Cisco Traffic Shaping
In this article we will show how to monitor network health from the client perspective using our AreWeDown tool. We will then disrupt communication from the client perspective to the server by using a ping flood, and will solve the problem using traffic shaping. Let’s start out with a healthy network: | 2005-08-06 08:13:50 | […]
