Subject: [OSPF] Security Extension for OSPFv2 when using Manual Key Management

From: shraddha <[email-masked]>
Date: Mon, 24 Jan 2011 11:51:22 +0530

Hi Sam,

In section 2, while explaining the challenge response solution
For a new router coming up on the LAN is described, a router changes it's 
Nonce when it detects a new node on the LAN.

1. This feature can be used to launch DOS attacks and cause a router to
change the nonce continuously. However I cannot think of a completely secure
solution to avoid DOS but introducing a minimum time (Similar to
MinLSArrival) to change the nonce might be helpful to reduce the effect. 

2. When a node detects change in the nonce in a hello message, it might have
to send hello immediately to ensure it's adjacency as it's some of the
previous hellos might be dropped by the router which changed the nonce.
This can be mentioned explicitly in the Receive packet handling section.

3. As I understand, the nonce is not checked for messages other than hello
so it can be removed from the trailer for other messages?

Rgds
Shraddha

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