Question

How to setup RA Guard?


Is there a guide to setting up RA Guard? I thought I saw one once, but I can't find it now. It doesn't seem to be covered in the 15.3 concepts guide, and I can't find a newer concepts guide (getting 404 page not found errors).

3 replies

Userlevel 2
Hi,

you need to create an ingress ACL with the "icmp-type" match criteria. If you plan to look at both L2 and L3 headers, you need double-wide ACL, which are not supported on every platforms.On which platform do you plan to use it?

Edit:
btw, you will find the EXOS documentations at the following link
http://www.extremenetworks.com/support/extreme-support/documentation/
Summit 460 and 480
Userlevel 2
The below example would help prevent RA attacks:

entry disallow_and_log_RA_attacks {if {protocol icmpv6;icmp-type 134;} then { deny; mirror-cpu; log; count RA_attack;}}

entry allow_tcp { if {protocol tcp; first-fragments;} then {permit;}}

entry allow_udp { if {protocol udp; first-fragments;} then {permit;}}

entry allow_icmp { if {protocol icmpv6; first-fragments;} then {permit;}}

entry allow_xyz…

entry denyall { if {first-fragments; } then {deny;}}

The allow_icmp rule can be a security exposure on certain hardware (I believe x480 is such). So you may want to make a more specific icmp rule looking for specific icmp_type that are authorized, and drop IPv6 icmp with extension headers.

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