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I have some head crunch issues with updating my Ubuntu 12.04 server system. When I issue the following command (as root):

apt-get update

...nothing happens and after a while apt-get gives up with loads of errors like:

W: Failed to fetch Unable to connect to

Below a copy of the stdout. Please note that I didn't wait for the command to finish and aborted it with CTRL-C to save some time

root@webserver:/var/log/apt# apt-get update 0% [Connecting to (]^C

This is how my sources.list looks like:

root@webserver:/var/log/apt# cat /etc/apt/sources.list
###### Ubuntu Main Repos
deb precise main restricted 
deb-src precise main restricted 

###### Ubuntu Update Repos
deb precise-security main restricted 
deb precise-updates main restricted 
deb-src precise-security main restricted 
deb-src precise-updates main restricted 

My /etc/apt.apt.conf is empty and no proxy is in use

root@webserver:/var/log/apt# cat /etc/apt/apt.conf
root@webserver:/var/log/apt# echo $http_proxy

root@web-octoplus01:/var/log/apt# echo $HTTP_PROXY


Using the US mirrors ( gives the same result. Special with the US mirrors is that every third try it suddenly works! (Only the address works, the rest results in the same errors)

root@web-octoplus01:/var/log/apt# host has address has address has address has IPv6 address 2001:67c:1562::15 has IPv6 address 2001:67c:1562::13 has IPv6 address 2001:67c:1562::14

Can it be that my server is on some inconsistent black-list at Ubuntu? What do I not see?

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have you tried to use another server as source for your updates? – Alvar Sep 25 '13 at 14:16

1 Answer 1

Since the IPv4 version works, you can change the priority of the type of connection to the destination node from IPv6 to IPv4 in the /etc/gai.conf file (which controls the destination address selection).

uncomment the following in the document:

precedence ::ffff:0:0/96 100

As stated in the file, this way sites that prefer IPv4 connection can be connected with IPv4 instead of IPv6.

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