How to protect the router from attacking?

[patrick.zhang]

I have two DNS servers connectted to Cisco7513 router,recently,I found that there are lots of packet ssourced from diffrent IP address destinated to DNS server. The CPU utilization of 7513 was very high(up to 95%).

There are two output FE port in this router,I closed one port,the CPU utilization down.

I don't know why this happened.I think maybe the DNS servers were attacked .

Can you tell me a method to avoid this issue?

Should I do some change on the configuration of the router?

[a-vazquez]

If you are very worried about your network security, I would suggest that you go for an IDS, which will detect and warn you if any attacks takes place. Based on the alarms you can take immediate actions.