The Cisco PE router must be configured to ignore or drop all packets with any IP options.

Severity
Group ID
Group Title
Version
Rule ID
Date
STIG Version
mediumV-217001SRG-NET-000205-RTR-000016CISC-RT-000750SV-217001r945860_rule2024-11-253
Description
Packets with IP options are not fast-switched and therefore must be punted to the router processor. Hackers who initiate denial of service (DoS) attacks on routers commonly send large streams of packets with IP options. Dropping the packets with IP options reduces the load of IP options packets on the router. The end result is a reduction in the effects of the DoS attack on the router and on downstream routers.
ℹ️ Check
Review the router configuration to determine if it will ignore or drop all packets with IP options as shown in the examples below: ip options drop or ip options ignore If the router is not configured to drop or block all packets with IP options, this is a finding.
✔️ Fix
Configure the router to ignore or drop all packets with IP options as shown in the examples below: R4(config)#ip options ignore or R4(config)#ip options drop