Cita:
Iniciado por racanix 
Saludos.
Pareciera ser que tu problema es de red:
Err
http://es.archive.ubuntu.com karmic Release.gpg
No puedo iniciar la conexión a es.archive.ubuntu.com:80 (2001:720:c10:d::7). - connect (101:
Network is unreachable) [IP: 2001:720:c10:d::7 80]
ahora bien. pudieras realizar un ping a google.com y a
91.189.88.37 que es la direccion a la que no te conecta
saludos
root@webapp:/etc/apt# ping
www.google.com
PING
www.l.google.com (66.102.7.104) 56(84) bytes of data.
64 bytes from lax04s01-in-f104.1e100.net (66.102.7.104): icmp_seq=1 ttl=57 time=77.4 ms
64 bytes from lax04s01-in-f104.1e100.net (66.102.7.104): icmp_seq=2 ttl=57 time=76.6 ms
64 bytes from lax04s01-in-f104.1e100.net (66.102.7.104): icmp_seq=3 ttl=57 time=76.5 ms
64 bytes from lax04s01-in-f104.1e100.net (66.102.7.104): icmp_seq=4 ttl=57 time=83.0 ms
^C
---
www.l.google.com ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3007ms
rtt min/avg/max/mdev = 76.590/78.434/83.043/2.696 ms
root@webapp:/etc/apt# ping 91.189.88.37
PING 91.189.88.37 (91.189.88.37) 56(84) bytes of data.
64 bytes from 91.189.88.37: icmp_seq=1 ttl=50 time=198 ms
64 bytes from 91.189.88.37: icmp_seq=2 ttl=50 time=204 ms
64 bytes from 91.189.88.37: icmp_seq=3 ttl=50 time=193 ms
64 bytes from 91.189.88.37: icmp_seq=4 ttl=50 time=194 ms
^C
--- 91.189.88.37 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3004ms
rtt min/avg/max/mdev = 193.981/197.860/204.065/4.099 ms
root@webapp:/etc/apt#
Como puedes ver tengo respuesta desde cualquiera de los 2 sitios
Acabo de ir a un sitio que me auto generó el siguiente sources.list
################################################## ###########
################### OFFICIAL UBUNTU REPOS ###################
################################################## ###########
###### Ubuntu Main Repos
deb
http://mx.archive.ubuntu.com/ubuntu/ karmic main restricted universe
deb-src
http://mx.archive.ubuntu.com/ubuntu/ karmic main restricted universe
###### Ubuntu Update Repos
deb
http://mx.archive.ubuntu.com/ubuntu/ karmic-security main restricted universe
deb
http://mx.archive.ubuntu.com/ubuntu/ karmic-updates main restricted universe
deb
http://mx.archive.ubuntu.com/ubuntu/ karmic-proposed main restricted universe
deb
http://mx.archive.ubuntu.com/ubuntu/ karmic-backports main restricted universe
deb-src
http://mx.archive.ubuntu.com/ubuntu/ karmic-security main restricted universe
deb-src
http://mx.archive.ubuntu.com/ubuntu/ karmic-updates main restricted universe
deb-src
http://mx.archive.ubuntu.com/ubuntu/ karmic-proposed main restricted universe
deb-src
http://mx.archive.ubuntu.com/ubuntu/ karmic-backports main restricted universe
El sitio es
http://repogen.simplylinux.ch/