# Generating UDP Checksums in Packets to L2TP Peers

You can configure the router to generate a UDP data integrity checksum in data packets sent to an L2TP peer. The router always uses UDP checksums during transmission and reception of L2TP control packets. Generation of checksums is disabled by default.

- To enable generation of UDP checksums:
  host1(config)#l2tp checksum

  | Note: This command does not affect the way the router checks the UDP data integrity checksum in L2TP data packets that are received from an L2TP peer. The router checks all non-zero received checksums and discards the packet if a data integrity problem is detected. L2TP checksum generation support is available on an ES2 10G Uplink LM and an ES2 4G LM only. It is not supported on an ES2 10G LM and an ES2 10G ADV LM. If an ES2 10G LM or an ES2 10G ADV LM is present when L2TP checksum is enabled, the checksum is not calculated and its value is set to zero.

#### Related Documentation

- l2tp checksum