Quote Originally Posted by Zrebel
a valid concern and that is what md5 is all about. people seem to think that there can be data corruption after data transfer and it is common that people suggest to check the checksum if there is a problem but this is flawed thinking and for a long time I wondered why people still included them.
I can assure you that for the people who download from the mirrors there can and frequently is corruption. About 1/2 of all the downloads that I got from mirrors were corrupt before Knoppix by BitTorrent became available (I have gone into greater detail about the nature of this corruption in other posts and will not duplicate that here). Many of the "booting problems" that we tried to help people with over the years have proven to be problems that would have been caught quickly and solved if people had only checked the md5 sum instead of thinking "I don't know what this md5 is that they keep telling me to check, so I'll just ignore it". While I have seen at least one report of a corrupt ISO downloaded by BitTorrent, I have doubts about that considering all of BT's built-in error checking. But if one has any doubt the md5 comes down right along with the ISO.

Checking the md5 makes less sense for security to prevent someone delivering a compromised copy of the file, if you check it against the md5 that is on the same mirror. However, there has never been a case of a compromised Knoppix ISO on any of the official mirrors, and I expect this would be caught very quickly. If there is any doubt one should get the md5 file from the primary DE site, or at least a different mirror, and make the test.

If someone gets the ISO from some untrusted source, like a newsgroup or e-mule or some other high risk source, then they take their chances and I'm not too concerned about them, they likely have plenty of other problems anyway.


And, of course, as in this case, if you run an Internet connection without the protection of a hardware firewall, then examining every packet in and out of your system and going into a panic as soon as you see a packet to or from an unexpected source, is just wacky. I find it hard to accept that Albretch actually had two routers hacked, but there have been exploits found for a few routers and I believe Linksys was one. Many more routers are compromised by someone getting into the system first though (by a virus or trojan perhaps) and then gaining access to the router from there, or by improperly set security on the router remote management (properly set means turning it completely off, as well as damn "features" like upnp). I have been running a high speed conection 24x7 for close to 7 years. I have used many routers over the years (starting with a Linksys, moving on to many wireless routers). I have never been hacked. I have never had a virus. I monitor and log well enough that I would know if such things had happened. But I would never run without a router (I don't even use dial-up any more, the problems have become so bad on the Internet that a software firewall just isn't enough).