md5sum : 1 out of 4 is wrong!

yeehi · 10-19-2004, 04:03 AM

I used star downloader on a windows system to get the iso image files from my local mirror.
Only 1 of the final images had a good md5 sum.

What went wrong? Surely it cant be a hacker. Is it just a poor adsl line or what? These are the md5 sums of the image files before being burnt to cd...

ugge · 10-25-2004, 02:10 PM

If the MD5sum differe then the images are corrupt.
Try downloading with another program.

karlan · 10-25-2004, 04:06 PM

the program probaly sucks, plain and simple. Try it with a web browser, also well respected programs like getright are usually good about grabbing verbatim copies.

ugge · 10-26-2004, 07:45 AM

To retrieve the files using linux you could try the wget command.

apolinsky · 10-26-2004, 08:04 AM

You probably just used the browser to download the iso images. You have just learned empiracally that http, the browser protocol is far from exact. When you download iso images or something you want to be exactly right use ftp, wget, rsync as your method of download. Browsers are convenient, but inaccurate. When you look at a web page, it doesn't matter too much. When you download software, accuracy is critical.

karlan · 11-01-2004, 09:05 PM

yes, but HTTP is [currently] built on top of TCP (OSI model ), which will assure we receive a verbatim copy of everything. Also, TCP uses a checksum, as does IP just below it. I don't see why ftp would be any different than HTTP. Does it implement yet another hash

ugge · 11-02-2004, 04:03 AM

HTTP and FTP both benefit from the error control built into the TCP protocol, in contrast to TFTP that uses UDP.
I would say that even though FTP was designed for files transfer HTTP is better. Why?
FTP rely on two network connections, one for data transfer and the other for commands to and from the server.
FTP support two modes, ASCII and binary. Sending anything other than a plain text file using ASCII will ruin the file without telling you.

karlan · 11-02-2004, 05:18 PM

thats retarded, it needs to open two different ports?!!!!
I also think any ASCII transfers should be done client-side, NOT server!

apolinsky · 11-02-2004, 06:37 PM

All I can tell you is when I downloaded disks using http, I got very few correct md5sums. When I switched to ftp, wget, rsync or in the case of Debian jigdo-lite, I have never had a failed download. I have just downloaded all 14 sarge disks. All gave the correct md5sum.