Thanks for your answer. The system has been rebooted many times and now is up to date. These are the outputs of the command you asked:
nmcli con status: NOME UUID DISPOSITIVI PREDEFINITO VPN PERCORSO-MASTER Connessione via cavo 1 7d4d4567-ece4-4a0c-953e-20c96224f025 eth0 si no non impostato nm-dns-dnsmasq.conf server=10.20.0.11 server=10.20.0.12 resolv.conf # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8) # DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN nameserver 127.0.0.1 search intra.manutencoop.it ps -ef | grep dnsmasq nobody 4069 3592 0 16:08 ? 00:00:00 /usr/sbin/dnsmasq --no-resolv --keep-in-foreground --no-hosts --bind-interfaces --pid-file=/var/run/sendsigs.omit.d/network-manager.dnsmasq.pid --listen-address=127.0.0.1 --conf-file=/var/run/nm-dns-dnsmasq.conf --cache-size=0 --proxy-dnssec baiocco 20910 9213 0 16:23 pts/0 00:00:00 grep --color=auto dnsmasq ** Attachment added: "syslog" https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1016080/+attachment/3203254/+files/syslog -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1016080 Title: slow wired connectivity after upgrade to 12.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1016080/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs