A network administrator is reviewing a packet capture. The packet capture from inside of Cisco Secure Firewall Threat Defense shows the inbound TCP traffic. However, the outbound TCP traffic is not…

The problem specifically concerns missing outbound TCP traffic; including UDP traffic in the capture would not address the fundamental routing issue affecting TCP sessions.

Assigning a higher security level to the inside interface does not create a missing route; security levels control traffic flow based on zone trust, not routing paths.

When a firewall receives inbound traffic but fails to forward the corresponding outbound traffic, it typically indicates that the firewall lacks a valid route to the destination for the return path. Adding a route to the destination ensures that the Cisco Secure Firewall Threat Defense knows how to correctly forward the outbound TCP traffic from its outside interface, completing the connection.

Assigning a lower security level to the inside interface would decrease its trust level, which is counterproductive for an internal network and unrelated to resolving a missing route for outbound traffic.