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unconditional-src-learn

 

Syntax

Hierarchy Level

Release Information

Statement introduced in Junos OS Release 10.4R16.

Description

Enables the router to learn IP addresses from nonvalidated sources when proxy Address Resolution Protocol (ARP) is configured.

Caution

By default, the router learns IP addresses from validated sources only. When this statement is configured and proxy ARP is enabled on an unnumbered interface, the router responds to ARP requests from any IP address, which might lead to exploitable information disclosure. An attacker can poison the ARP cache and create a fake forwarding table entry for an IP address, effectively creating a denial of service for that subscriber or interface. Therefore, exercise caution when configuring this statement.

Required Privilege Level

interface—To view this statement in the configuration.

interface-control—To add this statement to the configuration.