I’ll confess to having a lot to learn about IP ethernet networking. I feel pretty comfortable with basic TCP/IP (v4), the concept of UDP vs. TCP ports, ICMP pings, etc… but ARP is something that I haven’t dabbled much with. It is, of course, a layer that TCP depends on. When a machine sends a packet to another machine, it sends an arp packet out to “discover” the hardware (MAC) address of the machine on the other end, so ARP underlies everything. These days ICMP is many times blocked by firewall rules. The default with XP’s software firewall is to block ICMP pings for instance.
Month: December 2005
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Network Security guide for the home or small business network – Part 14 – Alternative software
There are ways that risks can be avoided. Recently, there was what was called a zero-day exploit for Internet Explorer. As I write this, the exploit surfaced 3 weeks ago and tomorrow there will be a patch. The vulnerability would allow remote code execution through a vulnerability in the way javascript is handled. So, for that 3 week unpatched period, Internet Explorer in it’s default configuration is a sitting duck. Well, truth be told, there are other browser vulnerabilities, many unpatched. (That’s a common method for many spyware bugs to install.)
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Kontact/ korganizer “unable to save event”
OK – so as I have mentioned after upgrading to Mandriva 2006 I was looking at the possibility of moving from Evolution to Kontact as the main mail client. I moved contacts and got things massaged quite well. One of the neat features in Kontact is the ability to have multiple address-books/resource names. Anyway, I moved on to calendar items which given that some of what I do is recurring appointments is fairly easy to reconstruct if necessary. Anyway, I got those copied over and thought I’d take advantage of being able to use different calendar files to organize different things. For instance I thought – why don’t I do a seperate file for Holidays…
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Securing SSH
I REALLY like secure shell (SSH) for remote access to linux machines. You can do more than just a “telnet” like remote shell with it. (Port forwarding.) However, the default configuraton for the openssh-server is sometimes a bit less tight than I would like. For that reason on a new install, I usually like to make a few changes. I don’t know if I’ve mentioned this before, but I haven’t devoted a post JUST to this, so… here we go.
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A Tip for cleaning up an infected PC
There’s a joke that many people bring out when new Windows viruses hit big…. it goes along the lines of, “download a fix here” and the link points to a knoppix linux livecd download, or a Mandriva download disk, fedora/etc… Some say linux isn’t affected by as many viruses because it lacks market share, I would point out that server market share (take a look at how many linux web servers there are…) would seem to tip the scales a bit, but that’s not the point of this post. What is the point is this…. When you have a Windows pc that is infested what you should do is disconnect from the internet. The problem is, that typically prevents you from getting the tools you need to fix the machine.
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Network Security guide for the home or small business network – Part 13 – Your own worst enemy
Once upon a time I did an article about the biggest computer security vulnerability ever. I’ve also passed along the old “the most dangerous part of a car is the nut behind the wheel” joke. If you haven’t got it yet, the computer user can be the “weakest link”. Let’s face it, you’ve got antivirus, a firewall, all the current windows updates, antispyware and a website pops up. The website looks like Windows security center and says you have a virus and need to get official antivirus software.
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Migrating Contacts from Evolution to Kontact
I’ve toyed around with the idea of migrating everything over to Kontact for my mail. I’ve used Evolution since moving over to linux, but there are some things about Kontact that just seem slicker to me. While I was doing the install, I had the laptop setup to receive messages through IMAP and used Kontact as the client. There were a few features that I wanted to spend a bit more time with. So, the first thing is getting the data into Kontact.
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Merry Christmas and a Happy New Year
For those that read this I’d like to wish you all a Merry Christmas and a Happy New Year. I have several posts scheduled to come out each day through the 1st of the New Year, but will likely not be adding to that unless something big happens. I’ll also be taking the week away from scheduled computer appointments. I’m one of those people that has a hard time setting tasks aside, but this time of year is usually the best opportunity for me to have a week away from the typical routine of chasing computer problems.
I hope that everyone will have an opportunity during this Holiday season to reflect on those things that are truly important which aren’t necessarily those same things that we spend everyday working with.
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Tracking Santa Claus online
In the spirit of the day before Christmas, I’ve come across a couple links to help you track Santa Claus’ progress around the world. First up the Google Blog points out that you can track Santa with their Google Earth software. They have a link here that will open in Google Earth –UPDATE Christmas 2006–This years link for the Google KML is here. (if installed. Google Earth is a free download and requires hardware video acceleration. The other link is a web browser based tracker… Norad has been doing this for a few years, this years version is at this link. (Flashplayer required.)
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Network Security guide for the home or small business network – Part 12 – Antispyware
I’ve talked about Antivirus software as an essential. Today we’re going to look at Antispyware software. There is a difference. By definition a virus is a piece of software that infects other files or copies itself. A worm is a virus that spreads without user intervention. (From one open network port to another for instance.) Spyware is not necessarily in either category. Spyware is the name given to software that tracks online behavior, some may track online searches, some may be more invasive and track anything typed in to the computer!