Ubuntu – Why I do get error 101? How is the DNS involved

apt

I was getting Update information is outdated alert. I tried sudo apt-get update and got these errors:

W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/Release.gpg  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::13). - connect (101: Network is unreachable) [IP: 2001:67c:1562::13 80]
W: Failed to fetch http://repository.spotify.com/dists/stable/Release.gpg  Something wicked happened resolving 'repository.spotify.com:http' (-11 - System error)
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/main/i18n/Translation-en_IN  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::13). - connect (101: Network is unreachable) [IP: 2001:67c:1562::13 80]
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/main/i18n/Translation-en  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::13). - connect (101: Network is unreachable) [IP: 2001:67c:1562::13 80]
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/multiverse/i18n/Translation-en_IN  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::13). - connect (101: Network is unreachable) [IP: 2001:67c:1562::13 80]
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/multiverse/i18n/Translation-en  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::13). - connect (101: Network is unreachable) [IP: 2001:67c:1562::13 80]
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/restricted/i18n/Translation-en_IN  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::13). - connect (101: Network is unreachable) [IP: 2001:67c:1562::13 80]
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/restricted/i18n/Translation-en  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::13). - connect (101: Network is unreachable) [IP: 2001:67c:1562::13 80]
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/universe/i18n/Translation-en_IN  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::13). - connect (101: Network is unreachable) [IP: 2001:67c:1562::13 80]
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/universe/i18n/Translation-en  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::13). - connect (101: Network is unreachable) [IP: 2001:67c:1562::13 80]
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/universe/source/Sources  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::13). - connect (101: Network is unreachable) [IP: 2001:67c:1562::13 80]
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/main/source/Sources  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::13). - connect (101: Network is unreachable) [IP: 2001:67c:1562::13 80]
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/multiverse/source/Sources  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::13). - connect (101: Network is unreachable) [IP: 2001:67c:1562::13 80]
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/restricted/source/Sources  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::13). - connect (101: Network is unreachable) [IP: 2001:67c:1562::13 80]
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/main/binary-i386/Packages  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::13). - connect (101: Network is unreachable) [IP: 2001:67c:1562::13 80]
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/restricted/binary-i386/Packages  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::13). - connect (101: Network is unreachable) [IP: 2001:67c:1562::13 80]
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/universe/binary-i386/Packages  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::13). - connect (101: Network is unreachable) [IP: 2001:67c:1562::13 80]
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/multiverse/binary-i386/Packages  Cannot initiate the connection to security.ubuntu.com:80 (2001:67c:1562::13). - connect (101: Network is unreachable) [IP: 2001:67c:1562::13 80]

E: Some index files failed to download. They have been ignored, or old ones used instead.

I followed this thread's top answer and it fixed the problem.

But someone please explain what was the problem and how did it got fixed?

Best Answer

If you are getting those kind of errors it means that either, your IPv6 connection was unstable, or the servers were dead, or the file was not found. Right now is working through:

http://[2001:67c:1562::13]/ubuntu/dists/raring-security/multiverse/binary-i386/