Cisco IP Phone 6921 not register while the other IP Phones is working fineWhat will be the cause of that problem? And how we can resolve this issue.

Cisco 2901 ISR I need help for my configuration.... although it is working fine but it is not secured cause everybody can access the internetI want to deny this IP range and permit only TMG server to have internet connection. My DHCP server is the 45...

I want to deny this IP range                 10.25.0.1 – 10.25.0.255                10.25.1.1 – 10.25.1.255Permit only 1 host                10.25.7.136  255.255.255.192 Using access-list. with the  Current configuration interface GigabitEthernet0/0i...

I want to deny this IP range                 10.25.0.1 – 10.25.0.255                10.25.1.1 – 10.25.1.255 Permit only 1 host                 10.25.7.136  255.255.255.192  Using access-list. ( Current configuration  ) ip nat inside source list 101 i...