Monitoring & Logging Links

Hi!
I have been facing some problem with my ISP link (satellite), it happens occasionally that there is no reply from there DNS server or any outside node. Now to monitor this i have to keep pinging the DNS server which is something very silly.

Is there any tool or way i can monitor this link and able to log its activity automatically. The network is designed in the following manner: -

satellite => Indoor unit => My Cisco Router's WAN interface

Router LAN is connected to my Server and from there the internal network is linked.

Is it possible that i Enable SNMP on the router and put a trigger to update me the link status when change, if its then i need some help in how to do this.

Thanx