404 Error from xenial-security main amd64 packages only, why could this be occurring?

Question

I've been having trouble recently getting updates from the security.ubuntu.com/ubuntu repository, but interestingly; it only has trouble with the amd64 packages. See the following excerpt from running sudo apt-get update:

Ign:54 http://ddebs.ubuntu.com xenial-security/multiverse amd64 Packages
Ign:55 http://ddebs.ubuntu.com xenial-security/multiverse i386 Packages
Ign:56 http://ddebs.ubuntu.com xenial-security/multiverse all Packages
Ign:57 http://ddebs.ubuntu.com xenial-security/multiverse Translation-en_US
Ign:58 http://ddebs.ubuntu.com xenial-security/multiverse Translation-en
Ign:59 http://ddebs.ubuntu.com xenial-security/multiverse amd64 DEP-11 Metadata
Ign:60 http://ddebs.ubuntu.com xenial-security/multiverse DEP-11 64x64 Icons
Err:30 http://ddebs.ubuntu.com xenial-security/main amd64 Packages
  404  Not Found
Ign:31 http://ddebs.ubuntu.com xenial-security/main i386 Packages
Ign:33 http://ddebs.ubuntu.com xenial-security/main all Packages
Ign:34 http://ddebs.ubuntu.com xenial-security/main Translation-en_US
Ign:36 http://ddebs.ubuntu.com xenial-security/main Translation-en
Ign:38 http://ddebs.ubuntu.com xenial-security/main amd64 DEP-11 Metadata
Ign:39 http://ddebs.ubuntu.com xenial-security/main DEP-11 64x64 Icons
Ign:40 http://ddebs.ubuntu.com xenial-security/restricted amd64 Packages
Ign:41 http://ddebs.ubuntu.com xenial-security/restricted i386 Packages
Ign:42 http://ddebs.ubuntu.com xenial-security/restricted all Packages
Ign:43 http://ddebs.ubuntu.com xenial-security/restricted Translation-en_US

Specifically, apt-get reports that:

W: The repository 'http://ddebs.ubuntu.com xenial-security Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Failed to fetch http://ddebs.ubuntu.com/dists/xenial-security/main/binary-amd64/Packages  404  Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.

And indeed if I visit the address shown in the error in my browser, I only get a 404 page.

One thing I have noticed is that my /etc/apt/sources.list file which I have not changed does not reference ddebs.ubuntu.com at all instead it references security.ubuntu.com and archive.ubuntu.com, so why is apt-get using this address? If I browse to the same url at security.ubuntu.com then I do not get a 404!

Any Ideas?

Solution

Its a bit big for a comment, so I put it into an answer. Might be a hint for your troubleshooting.

Some times apt errors messages are not very helpful and can be quite misleading.

Those messages often come after a long list of 'sucessful' output lines. I get "No release file" usually when I had disconnected the network. Very often the outputs before were not taken from the network at all, so it is possible that a very later error tells you "unkown address".

Err:30 http://ddebs.ubuntu.com xenial-security/main amd64 Packages
404  Not Found
W: The repository 'http://ddebs.ubuntu.com xenial-security Release' does not have
a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially
dangerous to use.

Best thing is to check the address with a browser. In your case you seem to have determined that the address is not valid. This would match perfectly with the error messages.

Please note that not only /etc/apt/sources.list contains links to repositories, but also any file in /etc/apt/sources.list.d/.. You might have a file in there that links to 'ddebs.ubuntu.com'. If so, just delete it.

Also it seems that Update cancels any update operation as long as there is still any error message left. So I usually comment out every line in the sources.list file until I have no errors, when work my way forward again to find out which line causes the trouble. In my case its usually typos or bad PPAs. Once you have the exact line, its often not too difficult to check the path/address or see if there is trouble with some key or else.

Also I had good experiences with adding my target architecture explicitly in the sources.list file, e.t.

deb [arch=amd64] http://ddebs.ubuntu.com/.... xenial-security main 

Hope it helps.

PS: save you some typing and use "sudo apt update". There is no need to use 'apt-get' for the update command.

Comments

[user535733]

Try to reach it manually, ddebs.ubuntu.com, dists, ubuntu-security, and you will clearly see why you are getting 404s. Edit your sources to include sources that exist. If you wish us to review your sources, then please edit your question to include your sources.

[Quinn Jones]

I wanted to originally, but I was having trouble eliding the rule that I must have 10 reputation in order to post more than two links, and further I was having trouble convincing SO to stop interpreting the repo addresses as links. However; as I said at the end of the question there is no reference to ddebs.ubuntu.com in my sources.list only archive.ubuntu.com and security.ubuntu.com

[Quinn Jones]

I usually use apt, but I figured I'd go back an keep it simple for the purpose of asking for help!

[Quinn Jones]

Thank you for this, I did not know about the sources.list.d directory maybe that is the culprit.

[Quinn Jones]

In fact that did work! not sure how they got there but there was a list file in that directory pointing to ddebs, not sure how or why it got there! But once I renamed the files apt used security.ubuntu and archive.ubuntu as desired and update works appropriately!

[CatMan]

Glad I could help! Please mark the question as answered to close this post. Thx