Charly's Column The Sysadmin’s Daily Grind: Arpalert

Dec 01, 2006

Corporate policies prohibit the unauthorized connection of hardware to the company network, threatening dire consequences in the case of non-compliance. Fair enough, but how do you actually go about catching somebody trying to plug an illegal laptop into your Ethernet?

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Ask Klaus!

Nov 01, 2006
No Connection Thank you for the comments in the September 2006 Linux Magazine regarding my IBM R50e laptop. I have......
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Charly's Column The Sysadmin’s Daily Grind: Ethtool

Apr 01, 2006

A touchy LAN that plays like a movie diva can spoil any admin’s day. Ethtool to the rescue!

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Netfilter L7 Blocking protocols at Layer 7 with the L7 patch

Mar 01, 2006

If you need a tool for filtering protocols that doesn’t depend on the port, try L7, an IPTables patch that operates through regular expressions.

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TCP Hijacking Understanding and preventing TCP attacks

Sep 01, 2005

It is quite easy to take a TCP connection down using a RST attack, and this risk increases with applications that need long-term connections, such as VPNs, DNS zone transfers, and BGP. We’ll describe how a TCP attack can happen, and we’ll show you some simple techniques for protecting your network.

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Charly's Column The Sysadmin’s Daily Grind: Smokeping

May 01, 2005

If you do not receive a response to a ping, or if the response is seriously delayed, you might like to take this as a warning. But who wants to ping all day? You need a ping-based monitoring utility like Smokeping.

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