| 7.3 |  | Cisco VPN 3.5 Client |
| 7.3.5 |  | Setting MTU size |

| A maximum transmission unit (MTU) is the largest size packet or frame, specified in octets, which can be sent in a packet- or frame-based network, such as the Internet. Figure displays the SetMTU window, which is where administrators set the MTU size.

The VPN Client automatically sets the MTU size to approximately 1400 bytes. For unique applications where fragmentation is still an issue, SetMTU can change the MTU size to fit the specific scenario. In the Network Adapters, IPSec-only field, select the network adapter. As shown in Figure , the 3Com EtherLink is selected. In the MTU Options group box, set the MTU option size by selecting the appropriate radio button. Always reboot the PC for the MTU changes to take effect.