Don't Take Code Red Lightly
In confronting malware, there is nothing innovative about the new strains of Klez, Yaha, SirCam and Code Red. Yet all of these worms have demonstrated unprecedented staying power on the Internet despite the existence of patches, anti-virus signatures, personal firewall protection and Intrusion Detection technology. Why are these threats so prolific, and why do new threats gain traction so quickly if all they amount to are retread malicious code?
This paper analyzes the patterns of emerging malware and presents a strategy to assist network and security administrators in addressing "new" yet old threats.
Directory:
> IT > Network Systems
Date: 2003-03-28
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Why not differential backups?
I get this question frequently. It's usually triggered either because the tape device can't hold an entire backup set or because the time required for backup interferes with productive work. Most of the time this can be easily remedied by a larger or faster storage device, but someone is bound to bring up the idea of differential backups.
The idea is that you create a full backup that has everything, and from then on, you only backup the files that have changed. Presumably that's a smaller set of files and therefore this solves the space or time problems. Usually the full backup is refreshed on some schedule and the process starts again. There are variants on the theme; for example the differential may include all files that have changed since the last full backup rather than just those that have changed since the last differential. That sort of scheme eventually ends up with the differential containing any and all files that ever change, no matter how infrequently; the full backup is the source of everything else.
Directory:
> IT > Network Systems
Date: 2003-03-27
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Multitech RF550VPN SOHO VPN Router
Multitech's new SOHO RF550VPN Router is an inexpensive ($179.00 list ) Internet access router with VPN capabilities suitable for home or small office use.
Features not found in lower end products include
- Five (5) IPSEC VPN tunnels
- Automatic dialup to emergency ISP if WAN connection fails
- Both client and WAN side filtering
- Virtual servers (inward port redirection)
- Redirect RF550VPN logging to a syslog server
- Flash upgradable firmware
Directory:
> IT > Network Systems
Date: 2003-03-27
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Documenting Your Network
Undocumented networks are extremely common. Many times this is related more to the difficulty of keeping the documentation up to date rather than to the difficulty of the documentation process itself. Many LAN Administrators had big dreams at one time of keeping elaborate drawings detailing every last aspect of the network. However, networks tend to change too frequently for such drawings to stay current. In spite of the difficulty, having a well documented network can help you solve problems quickly when they arise and is vital to the overall security of your network. In this article, we’ll discuss some alternative documentation methods that are more practical in the ever changing world of networks.
Directory:
> IT > Network Systems
Date: 2003-03-26
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Backlinks (http_referrers)
When a web page is accessed by a link from some other page, the address of the other page (the "referring page") is made available to the web server. We can pick that information up from logs or as the page is being displayed. For example, if we have Server Side Includes or php, we can pickup the referring page from an environment variable. Here's a snippet of Perl code that does that:
$frompage=$ENV{HTTP_REFERER};
$thispage=$ENV{REQUEST_URI};
Yes, there's a missing R in HTTP_REFERER. Yes, that's wrong, but that's what the variable is so that's what you use.
Directory:
> IT > Network Systems
Date: 2003-03-26
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Understanding IPTABLES
Disclaimer
Packet filtering is something I've always hard a hard time getting my head around. Not the basics; that's easy
enough. It's just the incredible level of detail, the difficulty of keeping it all in your head at once.
And then, of course, there are all the different flavors: ipfw, ipfilters, ipchains, and now iptables. It gets more
than a little confusing, and I've never taken the time for more than a cursory look at any of them.
Directory:
> IT > Network Systems
Date: 2003-03-25
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Why run your own mail server?
Disclaimer
First, The Consultant
Recently I was working with another "consultant". I've deliberately put that in quotes because this person really lacked the skills to do the job he was doing, but for political reasons I had to refrain from pushing him out of the way and taking over. His lack of basic knowledge was frustrating, but I gritted my teeth and kept my comments friendly. It wasn't easy.
Anyway, part of what he was doing was configuring a router. I had to hold my breath as he explained that he always left the default password unchanged because "it's easy to remember". After he left, and with the permission of the owner, I changed that. It's just this funny idea I have that a router sitting on the Internet ought not to have a password that is known by a few million people and published on hundreds of websites. I'm funny like that.
Directory:
> IT > Network Systems
Date: 2003-03-25
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Dell's wireless choice as simple as a, b, g
Latitude notebooks offered with choice of Intel or Dell wireless technology. Dell has responded to customer demands for more networking flexibility by offering a choice of wireless technologies in its latest laptops.
Directory:
> IT > Network Systems
Date: 2003-03-24
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The Network Router as Unsung Hero
Greater intelligence in routers could enable them to look inside a data packet and, for example, determine the content of a packet, according to IDC research manager Paul Strauss.
Directory:
> IT > Network Systems
Date: 2003-03-20
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Cisco To Bolster Linksys Product Line
Cisco Systems plans to beef up newly acquired Linksys products to improve the overall price/performance and functionality of those offerings, said Charlie Giancarlo, senior vice president and general manager of product development at Cisco.
Directory:
> IT > Network Systems
Date: 2003-03-20
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A Linux Fax Server for a Windows Network
Introduction
The firm I work for had a fax system integrated in the corporate e-mail platform, Microsoft Exchange, for sending and receiving. One day after a software upgrade, the system broke. We needed to find something with the equivalent functionality but with the following conditions:
Directory:
> IT > Network Systems
Date: 2003-03-03
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