Change the PPPOE MTU Size (Windows XP)
Category: Home > Network > Protocols > TCP-IP
By default, a Windows XP PPPoE connection uses an MTU size that is 20 bytes less than the IP MTU of the LAN adapter over which the PPPoE packets are sent, which in most cases is 1480 bytes. If a lower MTU is required, then this tweak can be used to change the value.
Open your registry and find the key below.
Create three new DWORD values called "ProtocolType", "PPPProtocolType" and "ProtocolMTU". Set their values according to the table below.
- ProtocolType = "2048" (in decimal)
- PPPProtocolType = "33" (in decimal)
- ProtocolMTU = to the required MTU size. (Windows will use the lesser of this value and the default.)
Restart Windows for the change to take effect.
Note: The default and maximum PPPoE MTU size in Windows XP is 1,480 bytes.
 |  |  |  |  |
|  | (Default) | REG_SZ | (value not set) | |
|  | ProtocolType | REG_DWORD | 0x00000800 (2048) | |
| | PPPProtocolType | REG_DWORD | 0x00000021 (33) | |
| | ProtocolMTU | REG_DWORD | 0x000005c8 (1480) | |
 |
| HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Ndiswan\Parameters\... |  |
 |
| Settings: |
System Key: [HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Ndiswan\Parameters\
Protocols\0]
Name: ProtocolType, PPPProtocolType, ProtocolMTU
Type: REG_DWORD (DWORD Value)
|
Related Tweaks
Disclaimer: Modifying the registry can cause serious problems that may require you to reinstall your operating system. We cannot guarantee that problems resulting from modifications to the registry can be solved. Use the information provided at your own risk.
Last Modified: June 19, 2002
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