Editing Denial-of-service attack (section)

===TTL expiry attack===
It takes more router resources to drop a packet with a [[Time to live#IP packets|TTL]] value of 1 or less than it does to forward a packet with a higher TTL value. When a packet is dropped due to TTL expiry, the router CPU must generate and send an [[Internet Control Message Protocol#Time exceeded|ICMP time exceeded]] response. Generating many of these responses can overload the router's CPU.<ref>{{cite web |title=TTL Expiry Attack Identification and Mitigation |url=https://www.cisco.com/c/en/us/about/security-center/ttl-expiry-attack.html |publisher=[[Cisco Systems]] |access-date=2019-05-24}}</ref>