Understanding Asymmetric Routing Risks
Sophos, Tuesday, October 6th, 2026
Sophos explains how asymmetric routing breaks stateful firewall inspection, raises adversary-in-the-middle risk and disrupts cutovers.
Sophos Professional Services explains that asymmetric routing, where a connection's outbound and return traffic take different paths, creates inspection gaps for stateful next-generation firewalls that need to see both directions.
The problem can raise adversary-in-the-middle risk and cause application failures, and Sophos has seen firewall cutovers cost customers access to payroll systems on payday.
Common causes include misconfigured subnets and gateways, policy-based routing, SD-WAN, load balancing and multiple ISP links, so Sophos recommends designing security into network architecture and validating traffic paths before firewall migrations.