[c-nsp] ACL to block udp/0?

[Hank Nussbacher]

We encountered something strange.  We run IOS-XR 7.5.2 on ASR9K platform.

Had a user under udp/0 attack.  Tried to block it via standard ACL:


ipv4 access-list block-zero
  20 deny udp any any eq 0
  30 deny tcp any any eq 0
  40 permit ipv4 any any


Applied to interface:

  ipv4 access-group block-zero ingress
  ipv4 access-group block-zero egress


Yet, based on Kentik, we had no effect and the udp/0 attack just 
continued - as if the Cisco ACL is totally ignored.  Or am I missing 
something in the ACL listed above?


Thanks,

Hank