I've just swithched my network provider, but the nameserver
in /etc/resolv.conf is still set to the old providers.
The comment in /etc/resolv.conf states that it is created
automatically by networkManager. However, reboting the machined or restarting
netwrok manager did not change anything :-(
What am I missing, please?

Here is some info about my system:
-----------------------------------------------------------------------------
me@me-4u:~$ sudo /etc/init.d/networking restart
* Reconfiguring network interfaces... [ OK ]
-----------------------------------------------------------------------------
me@me-4u:~$ more /etc/resolv.conf
# Generated by NetworkManager
nameserver 192.168.1.101
nameserver 167.206.245.130
nameserver 167.206.245.129
-----------------------------------------------------------------------------
me@me-4u:~$ more /etc/resolv.conf
# Generated by NetworkManager
nameserver 192.168.1.101
nameserver 167.206.245.130
nameserver 167.206.245.129
-----------------------------------------------------------------------------
me@me-4u:~$ netstat -r
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
192.168.1.0 * 255.255.255.0 U 0 0 0 eth0
link-local * 255.255.0.0 U 0 0 0 eth0
default 192.168.1.1 0.0.0.0 UG 0 0 0 eth0
me@me-4u:~$ ifconfig
eth0 Link encap:Ethernet HWaddr 00:23:54:13:27:50
inet addr:192.168.1.101 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::223:54ff:fe13:2750/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:5239 errors:0 dropped:0 overruns:0 frame:0
TX packets:4082 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1877837 (1.8 MB) TX bytes:354695 (354.6 KB)
Interrupt:26 Base address:0xa000

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:3736 errors:0 dropped:0 overruns:0 frame:0
TX packets:3736 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:292256 (292.2 KB) TX bytes:292256 (292.2 KB)

Either /etc/resolv.conf gets populated with DNS info via NetworkManager (no idea where if not in /etc/NetworkManager/) or via your DHCP client if you use dhclient or equivalent. In case of the latter you could tweak things yourself manually, automagically updating settings probably are better, creating or adding relevant lines to /etc/dhclient-eth0.conf:
and restart networking. Note the IP addresses above are just for the example. Even though they work from about everywhere there's no special need to use Google, OpenDNS and Level 3 name servers.

Thank you.
I've modified resolv.conf manually, and dns is working.
How is it supposed to happen automatically?
This started when I switched service from Cablevision to VerizonFios.

OK but I hope you changed the DNS IP addresses to the ones your ISP provides you with?


I don't know. Maybe check the NetworkManager GUI or wherever else (/etc/sysconfig/network/profiles or /etc/sysconfig/network-scripts/*eth*) you can set connection details?