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This is the documentation for the 25.06 version. Looking for the documentation of the latest version? Have a look here.

Proxy ARP

With Proxy ARP, TNSR can respond to ARP requests for ranges of IPv4 addresses. This allows TNSR to receive traffic for those addresses without having the IP addresses configured on an interface or routed to TNSR. This can be effective if an endpoint has no control over the upstream routing, but has access to a range of addresses inside a single directly attached interface subnet.

Note

Since these addresses are not bound to any interface, they cannot be used for terminating traffic on TNSR itself, such as for local services.

Typical use cases for proxy ARP involve utilizing additional IP addresses inside a subnet for NAT purposes or even for more advanced scenarios such as using PVLAN isolation for multiple customers within a single large subnet.

See also

Proxy ARP Configuration

Configuring Proxy ARP involves defining ranges of IPv4 addresses for which TNSR will respond to ARP requests and the interfaces on which TNSR will receive those requests.

Users can define multiple interfaces and ranges; TNSR will respond on every defined interface for every address within the defined ranges. Interfaces and ranges may be defined in either order, but Proxy ARP will not be fully active unless at least one interface and range are configured.

To define a Proxy ARP interface, use the following command:

tnsr(config)# proxy-arp interface <name>

To define a Proxy ARP address range, use the following command:

tnsr(config)# proxy-arp range vrf default <start-address> - <end-address>

To define a single address, specify the same value for the start and end address.

Proxy ARP Example

This example instructs TNSR to respond to ARP requests it receives on the LAN interface for any IP address in the range 10.127.99.5 through 10.127.99.9:

tnsr(config)# proxy-arp interface LAN
tnsr(config)# proxy-arp range vrf default 10.127.99.5 - 10.127.99.9

Proxy ARP Status

To view a list of interfaces defined for Proxy ARP:

tnsr(config)# show proxy-arp interfaces
ARP proxy enabled on:
    LAN

To view a list of IP address ranges defined for Proxy ARP:

tnsr(config)# show proxy-arp ranges
00. range: 10.127.99.5 - 10.127.99.9 vrf default