After you install the hotfix that is described in security bulletin MS05-019 on a Windows XP Service Pack 2-based computer, the PMTU discovery process does not work correctly (921439)

SYMPTOMS

After you install the hotfix that is described in Microsoft security bulletin MS05-019 on a Microsoft Windows XP Service Pack 2 (SP2)-based computer, the Path Maximum Transfer Unit (PMTU) discovery process does not work correctly. Additionally, Internet Control Message Protocol (ICMP) messages are discarded without any action.

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

893066 MS05-019: Vulnerabilities in TCP/IP could allow remote code execution and denial of service

RESOLUTION

Hotfix information

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Windows XP service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/default.aspx?scid=fh;[LN];CNTACTMS

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

Prerequisites

You must have Microsoft Windows XP SP2 installed to apply this hotfix. For more information about how to obtain the latest Windows XP service pack, click the following article number to view the article in the Microsoft Knowledge Base:

322389 How to obtain the latest Windows XP service pack

Restart information

You must restart your computer after you apply this hotfix.

Hotfix replacement information

This hotfix is not replaced by any later hotfix.

Registry information

You do not have to create any registry keys or modify any registry keys to use any hotfixes that this package contains.

Hotfix file information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

File name	File version	File size	Date	Time
Ipnat.sys	5.1.2600.2774	135,296	11-Oct-2005	23:51