ICMP Problem

[Hitman]

Hi,

We have a strange problem about icmp echo request drop by the firewall.

Explanation:

Router A ------------- FW-------------Router B

Routrer A and B use RPR (Resilient Packet Ring) feature for rapid failover and netwok optimizing

This RPR feature is bidirectionnal:
Router A do ICMP echo request to Router B (every 1 second)
Router B do ICMP echo request to Router A (every 1 second)

The first ping sequence (Router A do ICMP echo request to Router B) is O.K. and not block by the firewall, the echo reply by router B not block either.
evething is O.K. so far.

But The sequence (Router B do ICMP echo request to Router A) is always drop by the firewall with the following message:

ICMP : Echo request: ICMP type 8 code 0: message info : icmp request sent by replying peer

The firewall thinks that the router B sould not do a echo request but a echo reply to the router A. Probably because the ping sequence by both router are overlapping and they have the same sequence number.

Do you have an idea how to solver this problem

Thans in advance