Newsflash Operations - Junos: Firewall filter fails to match on port

Firewall filters applied on MPC cards (Trio-based PFE) can fail port matching on packets causing the filter to not execute the actions specified in the 'then' clause.

Explanation

When configuring a stateless firewall filter on a system with Trio-based PFE modules (e.g. MX Series), any source or destination port matching condition may fail to match intended packets, causing the filter to not execute the actions specified in the 'then' clause.​​​​ Depending on the intent and design of the interface filter, this match failure may have unexpected impact on the router or follow-on filter clauses. For example, if traffic with a specific destination port was designed to be accepted, a later "reject all" clause may inadvertently discard wanted traffic. Conversely, if certain destination ports are meant to be dropped, malicious traffic may be consumed by the RE or forwarded on to downstream routers.
 
This issue only affects routers running Junos OS 13.3R3, 14.1R1, and 14.1R2. Additionally, this issue only affects IPv4 traffic. IPv6 port matching filters are unaffected by this issue.

Conclusion - Workaround

This issue is being tracked as PR1003494 and the following software releases have been updated to resolve this specific issue: 
Junos OS 13.3R3-S3​, 13.3R4, 14.1R3, 14.2R1, and all subsequent releases.
 
The customer is advised to upgrade to a release where the issue is resolved.
 
Voor meer informatie kunt u contact opnemen met Infradata op +31 (0)71 750 1525 of per mail naar support@infradata.nl.

Partners & references

Juniper Networks