Using the predefined ‘junos-web’ address object is a Juniper best practice. It’s maintained by Juniper and contains a curated, updated list of common web ports (like HTTP/HTTPS), making the policy more secure and manageable than a wide-open ‘any’ rule, while being simpler than managing a custom list.

Sessions stuck in FIN_WAIT or other TCP termination states are typically due to misconfigured TCP timeout values. The SRX has specific timeouts for TCP phases (e.g., `tcp-finwait-timeout`). If these are set too long, sessions will consume resources without clearing properly. This is a more common and direct cause than the other options.

In a route-based VPN, the tunnel is established by the IKE gateway and IPsec policy, but the traffic selection for encryption is often handled by proxy-ids. If the source/destination addresses in the security policy using ‘permit tunnel’ do not match the proxy-ids defined in the IPsec configuration, the traffic will not be associated with the correct tunnel, even if the SAs are up.

This follows the standard Juniper SRX deployment model. The internal LAN is placed in the ‘trust’ security zone, and the ‘host-inbound-traffic’ services (like dhcp) are enabled on this trusted interface. The external WAN interface is placed in the ‘untrust’ zone. This zone separation is fundamental for defining security policies.

The ‘show security flow session’ command has an ‘application’ detail extension that displays the Layer 7 application name (e.g., junos:HTTP, junos:FTP) that AppSecure/AppID has determined for each active session. This is crucial for verifying application-based policy enforcement and troubleshooting.

For a deny policy, sessions are terminated immediately. Therefore, to log them, you must log at session-close (`session-log session-close`). Logging at `session-init` would not work because the session is never fully initialized. This is a key distinction between logging for permit vs. deny policies.

Dynamic Port Address Translation (PAT), often called NAPT (Network Address Port Translation) or IP masquerading on SRX, is the standard method for mapping many private IPs to a single public IP. It uses source port translation to keep sessions distinct, which is ideal and predictable for outbound employee internet access.

While ‘show configuration’ shows the config, and ‘show security policies’ shows the rules, `show security match-policies` is the diagnostic tool. It simulates a packet flow through the compiled policy set for a given source, destination, and application, showing you the exact matching order and result, which is critical for troubleshooting.

The `match-direction` statement in a security policy is designed for this exact purpose. Setting `match-direction source-destination` means the policy only matches traffic that is part of an existing, reverse-direction session (i.e., the return traffic). This is more secure and precise than a general TCP permit rule.

Using the predefined ‘junos-web’ address object is a Juniper best practice. It’s maintained by Juniper and contains a curated, updated list of common web ports (like HTTP/HTTPS), making the policy more secure and manageable than a wide-open ‘any’ rule, while being simpler than managing a custom list.0