The tcp ipv6 min-mss command sets the minimum value of maximum segment size (MSS) for a TCP6 connection.
The undo tcp ipv6 min-mss command restores the default minimum value of the MSS for a TCP6 connection.
The default minimum MSS value for a TCP6 connection is 216 bytes.
| Parameter | Description | Value |
|---|---|---|
| mss-value | Specifies the minimum MSS value for a TCP6 connection. | The value ranges from 32 bytes to 1500 bytes. By default, the value is 216 bytes. |
Usage Scenario
To establish a TCP6 connection, the MSS value is negotiated, which indicates the maximum length of packets that the local device can receive. The TCP6 client on a network may send a request packet for establishing a TCP6 connection carrying a small MSS value. For example, the MSS value is 1. After the TCP6 server receives the request packet carrying the MSS value, the TCP6 connection is established. The TCP6 client then may send large numbers of requests to the server by an application, causing the TCP6 server to generate large numbers of reply packets. This may burden the TCP6 server or network, causing denial of service (DoS) attacks. To resolve this problem, run the tcp ipv6 min-mss command to set the minimum MSS value for a TCP6 connection. This configuration prevents a server from receiving packets carrying a small MSS value.
Precautions
The minimum MSS value configured using the tcp ipv6 min-mss command must be less than the maximum MSS value configured using the tcp ipv6 max-mss command.
If the tcp ipv6 min-mss command is run more than once in the same view, the latest configuration overrides the previous one.
Configure the parameters under the guidance of the technical personnel.