для Cisco Cisco IOS Software Release 12.2(14)S
TCP MSS Adjustment
How to Configure the TCP MSS Adjustment
3
Multiple Releases: (See the Feature History Table)
Verifying TCP MSS Adjustments
In the following examples, there are outputs that assist in verifying the TCP MSS adjustments.
Command Configured on Single Interface
Step 1
Configure the interface adjustment value.
interface ethernet1/1
ip tcp adjust 500
Step 2
Telnet from router A to router C, with B having the MSS adjustment configured.
telnet
00:09:15:%SYS-5-CONFIG_I: Configured from console by consolenet 1.0.1.3
Trying 1.0.1.3... Open
Step 3
Observe the debug output from router C.
*Mar 10 14:49:45.045: tcp0: I LISTEN 4.0.0.1:11001 1.0.1.3:23 seq 2012812244
OPTS 4 SYN WIN 4128
*Mar 10 14:49:45.045: TCP0: state was LISTEN -> SYNRCVD [23 -> 4.0.0.1(11001)]
*Mar 10 14:49:45.045: TCP0: Connection to 4.0.0.1:11001, received MSS 500,
MSS is 500
*Mar 10 14:49:45.045: TCP: sending SYN, seq 1091096877, ack 2012812245
The MSS gets adjusted to 500 as configured.
Step 5
ip mtu
bytes
Example:
Router(config-if) ip mtu 1491
Sets the MTU size of IP packets, in bytes, sent on an
interface.
interface.
Step 6
end
Example:
Router(config-if) end
Exits to global configuration mode.
Command or Action
Purpose