nat64 tcp adjust-mss

Function

The nat64 tcp adjust-mss command sets the maximum segment size (MSS) of packets sent by two interfaces without fragmentation.

The undo nat64 tcp adjust-mss command deletes the configured MSS of packets sent by two interfaces without fragmentation.

By default, the MSS value in TCP SYN packets after NAT64 processes the packets is not changed.

This command is supported only on the NetEngine 8000 F1A.

Format

nat64 tcp adjust-mss mss-value

undo nat64 tcp adjust-mss [ mss-value ]

Parameters

Parameter	Description	Value
mss-value	Sets the MSS value in TCP SYN packets.	The value is an integer ranging from 536 to 1460, in bytes.

Parameter

Description

Value

mss-value

Sets the MSS value in TCP SYN packets.

The value is an integer ranging from 536 to 1460, in bytes.

Views

NAT64 instance view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
nat	write

Usage Guidelines

Usage Scenario

The MSS value defined in TCP specifies the length of a TCP packet to be sent without fragmentation. Two devices exchange SYN packets to negotiate the MSS value for a TCP connection to be established.

Configuration Impact

After the nat64 tcp adjust-mss command is run in the NAT64 instance view, a CGN device changes the MSS value in all TCP packets that are processed by NAT64. If the negotiated MSS value is greater than the configured, the negotiated MSS value is changed to the configured value. If the negotiated MSS value is smaller than the configured, the negotiated MSS value remains unchanged.

Example

# Set the MSS value to 1000 bytes in a NAT64 instance named nat1.

<HUAWEI> system-view
[~HUAWEI] nat64 instance nat1 id 1
[*HUAWEI-nat64-instance-nat1] nat64 tcp adjust-mss 1000