RouterMTU Registry Value Is No Longer Supported

ID: Q162054

The information in this article applies to:

Microsoft Windows NT operating system version 3.1
Microsoft Windows NT Advanced Server version 3.1
Microsoft Windows NT Workstation versions 3.5, 3.51, 4.0
Microsoft Windows NT Server versions 3.5, 3.51, 4.0

SUMMARY

The Windows NT 3.5 Resource Kit documentation was not updated properly from version 3.1, and lists a number of invalid TCP/IP registry parameters. The parameters listed in this article should be used in their place. The Windows NT 3.5 TCP/IP stack was changed significantly from version 3.1, so many of the old parameters are no longer valid. The Windows NT 3.51 Resource Kit should include the necessary corrections.

MORE INFORMATION

Page 586 of Appendix B in "Optimizing Windows NT" from the Windows NT Resource Kit version 3.5 describes the RouterMTU registry parameter. RouterMTU functionality was replaced in Windows NT 3.5 by PMTU Discovery, as defined in RFC 1191.

For additional information on the usage of the RouterMTU parameter in Windows NT 3.1, see the following article in the Microsoft Knowledge Base:

ARTICLE-ID: Q102973
TITLE : REG: TCP/IP Transport Entries, PART 1

For additional information on PMTU Discovery, see the following article in the Microsoft Knowledge Base:

ARTICLE-ID: Q159211
TITLE : Diagnoses and Treatment of Black Hole Routers

Additional query words: mtu size prodnt request comment comments

Keywords : kbnetwork nttcp
Version : WINNT:3.1 3.5 3.51 4.0
Platform : winnt
Issue type : kbinfo