Which two features would satisfy this requirement?

You have deployed an SRX Series device at your network edge to secure Internet-bound sessions for your local hosts using source NAT. You want to ensure that your users are able to interact with applications on the Internet that require more than one TCP session for the same application session.

Which two features would satisfy this requirement? (Choose two.)
A . address persistence
B . STUN
C . persistent NAT
D . double NAT

View Answer

Answer: AC

Explanation:

Address persistence ensures that the same NAT IP address is used for all sessions originating from a single source IP. Persistent NAT maintains connections for applications needing multiple sessions, like VoIP. Additional details are available in Juniper NAT Documentation.

For applications that require multiple TCP sessions for the same application session (such as VoIP or certain online games), the SRX device needs to handle NAT properly to maintain session continuity. Here’s what helps:

Address Persistence (Answer A): Address persistence ensures that multiple sessions initiated by the same internal host are mapped to the same external IP address. This is crucial for applications that use multiple TCP sessions to maintain a stateful connection with the external server.

Command Example:

bash

set security nat source persistent-nat address-persistence

Persistent NAT (Answer C): This feature allows the external server to initiate new connections to the

internal client using the same NAT translation. It’s essential for applications that require consistent

NAT mappings across multiple sessions.

Command Example:

bash

set security nat source persistent-nat permit target-host-port

These features ensure that applications with multiple TCP sessions work seamlessly across NAT.

Reference: Juniper NAT and persistent NAT documentation.