Symptoms
Consider the following scenarios:
- The computers in a network environment run Windows 7 Service Pack 1 (SP1), Windows Server 2008 R2 SP1, Windows 8, Windows Server 2012, Windows 8.1, Windows Server 2012 R2, Windows RT 8.1.
- Path MTU (PMTU) discovery (EnablePMTUDiscovery) is enabled on the computers.
- The network environment is slow. Therefore, in order to increase the throughput, the MTU is required to be set to a value that is less than 576.
In this situation, the MTU is not set to less than 576 correctly. Therefore, data packets are dropped, and packet loss occurs during data transmission. This makes the network unreliable.
Cause
This issue occurs because PMTU discovery does not allow an MTU value that is less than 576. Therefore, data packets are fragmented excessively.
More Information
After you apply this hotfix you can use the Netsh.exe tool to verify the current minimum MTU for PMTU discovery. To do this, type
netsh interface ip show global
at the command prompt and press Enter. The value for "Minimum MTU" is the current minimum MTU for PMTU discovery.
To change the minimum MTU for PMTU discovery to a value such as 352, you can input
netshinterface ip set global minmtu=352
at the command prompt and press Enter.
To display the active setting for all interfaces you can also use the command
netsh interface ip show interfaces
For example:
Idx Met MTU State Name
1 50 4294967295 connected Loopback Pseudo-Interface 1
14 5 1500 connected Local Area Connection 2
Resolution
Hotfix information
A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.
If the hotfix is available for download, there is a "Hotfix Download Available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.
Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft website:
http://support.microsoft.com/contactus/?ws=support Note The "Hotfix Download Available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.
Prerequisites
To apply this hotfix, you must be running one of the following operating systems:
- Windows 7 SP1
- Windows Server 2008 R2 SP1
- Windows 8
- Windows Server 2012
- Windows RT 8.1
- Windows 8.1
- Windows Server 2012 R2
For more information about how to obtain a Windows 7 or Windows Server 2008 R2 service pack, click the following article number to view the article in the Microsoft Knowledge Base:
976932 Information about Service Pack 1 for Windows 7 and for Windows Server 2008 R2
Registry information
To apply this hotfix, you do not have to make any changes to the registry.
Restart requirement
You might have to restart the computer after you apply this hotfix.
Hotfix replacement information
This hotfix does not replace a previously released hotfix.
File information
The global version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.
Windows 7 and Windows Server 2008 R2 file information and notes
Important Windows 7 hotfixes and Windows Server 2008 R2 hotfixes are included in the same packages. However, hotfixes on the Hotfix Request page are listed under both operating systems. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 7/Windows Server 2008 R2" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.
The files that apply to a specific product, milestone (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:
Version Product Milestone Service branch 6.1.760
0.16xxxWindows 7 and Windows Server 2008 R2 RTM GDR 6.1.760
1.22xxxWindows 7 and Windows Server 2008 R2 SP1 LDR GDR service branches contain only those fixes that are widely released to address widespread, critical issues. LDR service branches contain hotfixes in addition to widely released fixes.
The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows 7 and for Windows Server 2008 R2" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are critical to maintaining the state of the updated component. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.
For all supported x86-based versions of Windows 7
| File name | File version | File size | Date | Time | Platform |
|---|---|---|---|---|---|
| Netio.sys | 6.1.7601.22477 | 240,576 | 10-Oct-13 | 11:51 | x86 |
| Fwpkclnt.sys | 6.1.7601.22477 | 187,840 | 10-Oct-13 | 11:51 | x86 |
| Tcpip.sys | 6.1.7601.22477 | 1,309,632 | 10-Oct-13 | 11:51 | x86 |
| Arp.exe | 6.1.7600.16385 | 20,992 | 14-Jul-09 | 1:14 | x86 |
| Finger.exe | 6.1.7600.16385 | 10,240 | 14-Jul-09 | 1:14 | x86 |
| Hostname.exe | 6.1.7600.16385 | 8,704 | 14-Jul-09 | 1:14 | x86 |
| Mrinfo.exe | 6.1.7600.16385 | 11,264 | 14-Jul-09 | 1:14 | x86 |
| Netiohlp.dll | 6.1.7601.22477 | 178,688 | 10-Oct-13 | 11:47 | x86 |
| Netstat.exe | 6.1.7601.22477 | 28,160 | 10-Oct-13 | 11:10 | x86 |
| Route.exe | 6.1.7600.16385 | 17,920 | 14-Jul-09 | 1:14 | x86 |
| Tcpsvcs.exe | 6.1.7600.16385 | 9,216 | 14-Jul-09 | 1:14 | x86 |
For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2
| File name | File version | File size | Date | Time | Platform |
|---|---|---|---|---|---|
| Netio.sys | 6.1.7601.22477 | 376,768 | 10-Oct-13 | 12:18 | x64 |
| Fwpkclnt.sys | 6.1.7601.22477 | 288,192 | 10-Oct-13 | 12:18 | x64 |
| Tcpip.sys | 6.1.7601.22477 | 1,896,896 | 10-Oct-13 | 12:18 | x64 |
| Arp.exe | 6.1.7600.16385 | 24,064 | 14-Jul-09 | 1:38 | x64 |
| Finger.exe | 6.1.7600.16385 | 11,264 | 14-Jul-09 | 1:39 | x64 |
| Hostname.exe | 6.1.7600.16385 | 9,728 | 14-Jul-09 | 1:39 | x64 |
| Mrinfo.exe | 6.1.7600.16385 | 12,800 | 14-Jul-09 | 1:39 | x64 |
| Netiohlp.dll | 6.1.7601.22477 | 229,888 | 10-Oct-13 | 12:14 | x64 |
| Netstat.exe | 6.1.7601.22477 | 33,792 | 10-Oct-13 | 11:30 | x64 |
| Route.exe | 6.1.7600.16385 | 21,504 | 14-Jul-09 | 1:39 | x64 |
| Tcpsvcs.exe | 6.1.7600.16385 | 10,240 | 14-Jul-09 | 1:39 | x64 |
| Arp.exe | 6.1.7600.16385 | 20,992 | 14-Jul-09 | 1:14 | x86 |
| Finger.exe | 6.1.7600.16385 | 10,240 | 14-Jul-09 | 1:14 | x86 |
| Hostname.exe | 6.1.7600.16385 | 8,704 | 14-Jul-09 | 1:14 | x86 |
| Mrinfo.exe | 6.1.7600.16385 | 11,264 | 14-Jul-09 | 1:14 | x86 |
| Netiohlp.dll | 6.1.7601.22477 | 178,688 | 10-Oct-13 | 11:47 | x86 |
| Netstat.exe | 6.1.7601.22477 | 28,160 | 10-Oct-13 | 11:10 | x86 |
| Route.exe | 6.1.7600.16385 | 17,920 | 14-Jul-09 | 1:14 | x86 |
| Tcpsvcs.exe | 6.1.7600.16385 | 9,216 | 14-Jul-09 | 1:14 | x86 |
For all supported IA-64-based versions of Windows Server 2008 R2
| File name | File version | File size | Date | Time | Platform |
|---|---|---|---|---|---|
| Netio.sys | 6.1.7601.22477 | 711,104 | 10-Oct-13 | 11:21 | IA-64 |
| Fwpkclnt.sys | 6.1.7601.22477 | 482,752 | 10-Oct-13 | 11:20 | IA-64 |
| Tcpip.sys | 6.1.7601.22477 | 3,806,144 | 10-Oct-13 | 11:21 | IA-64 |
| Arp.exe | 6.1.7600.16385 | 48,128 | 14-Jul-09 | 1:44 | IA-64 |
| Finger.exe | 6.1.7600.16385 | 22,528 | 14-Jul-09 | 1:44 | IA-64 |
| Hostname.exe | 6.1.7600.16385 | 14,336 | 14-Jul-09 | 1:44 | IA-64 |
| Mrinfo.exe | 6.1.7600.16385 | 29,184 | 14-Jul-09 | 1:44 | IA-64 |
| Netiohlp.dll | 6.1.7601.22477 | 406,016 | 10-Oct-13 | 11:17 | IA-64 |
| Netstat.exe | 6.1.7601.22477 | 71,168 | 10-Oct-13 | 10:52 | IA-64 |
| Route.exe | 6.1.7600.16385 | 45,568 | 14-Jul-09 | 1:44 | IA-64 |
| Tcpsvcs.exe | 6.1.7600.16385 | 18,944 | 14-Jul-09 | 1:45 | IA-64 |
| Arp.exe | 6.1.7600.16385 | 20,992 | 14-Jul-09 | 1:14 | x86 |
| Finger.exe | 6.1.7600.16385 | 10,240 | 14-Jul-09 | 1:14 | x86 |
| Hostname.exe | 6.1.7600.16385 | 8,704 | 14-Jul-09 | 1:14 | x86 |
| Mrinfo.exe | 6.1.7600.16385 | 11,264 | 14-Jul-09 | 1:14 | x86 |
| Netiohlp.dll | 6.1.7601.22477 | 178,688 | 10-Oct-13 | 11:47 | x86 |
| Netstat.exe | 6.1.7601.22477 | 28,160 | 10-Oct-13 | 11:10 | x86 |
| Route.exe | 6.1.7600.16385 | 17,920 | 14-Jul-09 | 1:14 | x86 |
| Tcpsvcs.exe | 6.1.7600.16385 | 9,216 | 14-Jul-09 | 1:14 | x86 |
Windows 8 and Windows Server 2012 file information and notes
The files that apply to a specific product, milestone (RTM,SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:
Version Product Milestone Service branch 6.2.920 0.16 xxx Windows 8 and Windows Server 2012 RTM GDR 6.2.920 0.20 xxx Windows 8 and Windows Server 2012 RTM LDR GDR service branches contain only those fixes that are widely released to address widespread, critical issues. LDR service branches contain hotfixes in addition to widely released fixes.
The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows RT, Windows 8, and Windows Server 2012" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.
For all supported x86-based versions of Windows 8
| File name | File version | File size | Date | Time | Platform |
|---|---|---|---|---|---|
| Fwpkclnt.sys | 6.2.9200.16384 | 271,088 | 26-Jul-2012 | 03:30 | x86 |
| Tcpip.sys | 6.2.9200.20885 | 1,815,384 | 25-Nov-2013 | 23:56 | x86 |
| Arp.exe | 6.2.9200.16384 | 22,016 | 26-Jul-2012 | 03:20 | x86 |
| Finger.exe | 6.2.9200.20885 | 13,312 | 25-Nov-2013 | 23:32 | x86 |
| Hostname.exe | 6.2.9200.16384 | 11,776 | 26-Jul-2012 | 03:20 | x86 |
| Mrinfo.exe | 6.2.9200.16384 | 13,312 | 26-Jul-2012 | 03:20 | x86 |
| Netiohlp.dll | 6.2.9200.20886 | 201,728 | 25-Nov-2013 | 23:32 | x86 |
| Netstat.exe | 6.2.9200.16384 | 32,256 | 26-Jul-2012 | 03:20 | x86 |
| Route.exe | 6.2.9200.16384 | 19,456 | 26-Jul-2012 | 03:20 | x86 |
| Tcpsvcs.exe | 6.2.9200.16384 | 10,752 | 26-Jul-2012 | 03:20 | x86 |
For all supported x64-based versions of Windows 8 and of Windows Server 2012
| File name | File version | File size | Date | Time | Platform |
|---|---|---|---|---|---|
| Fwpkclnt.sys | 6.2.9200.16384 | 411,888 | 26-Jul-2012 | 04:43 | x64 |
| Tcpip.sys | 6.2.9200.20885 | 2,228,568 | 25-Nov-2013 | 23:40 | x64 |
| Arp.exe | 6.2.9200.16384 | 25,088 | 26-Jul-2012 | 03:08 | x64 |
| Finger.exe | 6.2.9200.20885 | 14,848 | 25-Nov-2013 | 23:29 | x64 |
| Hostname.exe | 6.2.9200.16384 | 13,312 | 26-Jul-2012 | 03:08 | x64 |
| Mrinfo.exe | 6.2.9200.16384 | 15,360 | 26-Jul-2012 | 03:08 | x64 |
| Netiohlp.dll | 6.2.9200.20886 | 248,320 | 25-Nov-2013 | 23:28 | x64 |
| Netstat.exe | 6.2.9200.16384 | 38,912 | 26-Jul-2012 | 03:08 | x64 |
| Route.exe | 6.2.9200.16384 | 22,528 | 26-Jul-2012 | 03:08 | x64 |
| Tcpsvcs.exe | 6.2.9200.16384 | 11,264 | 26-Jul-2012 | 03:08 | x64 |
| Arp.exe | 6.2.9200.16384 | 22,016 | 26-Jul-2012 | 03:20 | x86 |
| Finger.exe | 6.2.9200.20885 | 13,312 | 25-Nov-2013 | 23:32 | x86 |
| Hostname.exe | 6.2.9200.16384 | 11,776 | 26-Jul-2012 | 03:20 | x86 |
| Mrinfo.exe | 6.2.9200.16384 | 13,312 | 26-Jul-2012 | 03:20 | x86 |
| Netiohlp.dll | 6.2.9200.20886 | 201,728 | 25-Nov-2013 | 23:32 | x86 |
| Netstat.exe | 6.2.9200.16384 | 32,256 | 26-Jul-2012 | 03:20 | x86 |
| Route.exe | 6.2.9200.16384 | 19,456 | 26-Jul-2012 | 03:20 | x86 |
| Tcpsvcs.exe | 6.2.9200.16384 | 10,752 | 26-Jul-2012 | 03:20 | x86 |
Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 file information and notes
Important Windows 8.1 and Windows Server 2012 R2 hotfixes are included in the same packages.
The files that apply to a specific product, milestone (RTM,SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:
Version Product Milestone Service branch 6.2.920 0.20 xxx Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 RTM LDR The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows RT, Windows 8, and Windows Server 2012" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.
For Windows RT 8.1
| File name | File version | File size | Date | Time | Platform |
|---|---|---|---|---|---|
| Fwpkclnt.sys | 6.3.9600.16384 | 278,888 | 22-Aug-2013 | 03:52 | Not applicable |
| Tcpip.sys | 6.3.9600.16477 | 1,753,440 | 27-Nov-2013 | 11:06 | Not applicable |
| Arp.exe | 6.3.9600.16384 | 21,504 | 22-Aug-2013 | 02:18 | Not applicable |
| Finger.exe | 6.3.9600.16477 | 13,312 | 27-Nov-2013 | 08:30 | Not applicable |
| Hostname.exe | 6.3.9600.16384 | 12,288 | 22-Aug-2013 | 02:18 | Not applicable |
| Mrinfo.exe | 6.3.9600.16384 | 13,824 | 22-Aug-2013 | 02:16 | Not applicable |
| Netiohlp.dll | 6.3.9600.16477 | 146,432 | 27-Nov-2013 | 08:12 | Not applicable |
| Netstat.exe | 6.3.9600.16384 | 29,696 | 22-Aug-2013 | 02:13 | Not applicable |
| Route.exe | 6.3.9600.16384 | 18,432 | 22-Aug-2013 | 02:14 | Not applicable |
| Tcpsvcs.exe | 6.3.9600.16384 | 10,752 | 22-Aug-2013 | 02:19 | Not applicable |
For all supported x86-based versions of Windows 8.1
| File name | File version | File size | Date | Time | Platform |
|---|---|---|---|---|---|
| Fwpkclnt.sys | 6.3.9600.16384 | 286,048 | 22-Aug-2013 | 05:20 | x86 |
| Tcpip.sys | 6.3.9600.16477 | 1,883,992 | 27-Nov-2013 | 13:45 | x86 |
| Arp.exe | 6.3.9600.16384 | 22,528 | 22-Aug-2013 | 02:52 | x86 |
| Finger.exe | 6.3.9600.16477 | 13,312 | 27-Nov-2013 | 09:20 | x86 |
| Hostname.exe | 6.3.9600.16384 | 12,288 | 22-Aug-2013 | 02:52 | x86 |
| Mrinfo.exe | 6.3.9600.16384 | 14,848 | 22-Aug-2013 | 02:50 | x86 |
| Netiohlp.dll | 6.3.9600.16477 | 167,936 | 27-Nov-2013 | 08:56 | x86 |
| Netstat.exe | 6.3.9600.16384 | 32,768 | 22-Aug-2013 | 02:46 | x86 |
| Route.exe | 6.3.9600.16384 | 19,968 | 22-Aug-2013 | 02:47 | x86 |
| Tcpsvcs.exe | 6.3.9600.16384 | 10,752 | 22-Aug-2013 | 02:54 | x86 |
For all supported x64-based versions of Windows 8 and of Windows Server 2012 R2
| File name | File version | File size | Date | Time | Platform |
|---|---|---|---|---|---|
| Fwpkclnt.sys | 6.3.9600.16384 | 428,896 | 22-Aug-2013 | 12:34 | x64 |
| Tcpip.sys | 6.3.9600.16477 | 2,543,960 | 27-Nov-2013 | 15:32 | x64 |
| Arp.exe | 6.3.9600.16384 | 25,088 | 22-Aug-2013 | 10:01 | x64 |
| Finger.exe | 6.3.9600.16477 | 15,360 | 27-Nov-2013 | 09:47 | x64 |
| Hostname.exe | 6.3.9600.16384 | 13,312 | 22-Aug-2013 | 10:02 | x64 |
| Mrinfo.exe | 6.3.9600.16384 | 15,360 | 22-Aug-2013 | 09:59 | x64 |
| Netiohlp.dll | 6.3.9600.16477 | 203,264 | 27-Nov-2013 | 09:10 | x64 |
| Netstat.exe | 6.3.9600.16384 | 38,400 | 22-Aug-2013 | 09:52 | x64 |
| Route.exe | 6.3.9600.16384 | 23,040 | 22-Aug-2013 | 09:53 | x64 |
| Tcpsvcs.exe | 6.3.9600.16384 | 11,264 | 22-Aug-2013 | 10:03 | x64 |
| Arp.exe | 6.3.9600.16384 | 22,528 | 22-Aug-2013 | 02:52 | x86 |
| Finger.exe | 6.3.9600.16477 | 13,312 | 27-Nov-2013 | 09:20 | x86 |
| Hostname.exe | 6.3.9600.16384 | 12,288 | 22-Aug-2013 | 02:52 | x86 |
| Mrinfo.exe | 6.3.9600.16384 | 14,848 | 22-Aug-2013 | 02:50 | x86 |
| Netiohlp.dll | 6.3.9600.16477 | 167,936 | 27-Nov-2013 | 08:56 | x86 |
| Netstat.exe | 6.3.9600.16384 | 32,768 | 22-Aug-2013 | 02:46 | x86 |
| Route.exe | 6.3.9600.16384 | 19,968 | 22-Aug-2013 | 02:47 | x86 |
| Tcpsvcs.exe | 6.3.9600.16384 | 10,752 | 22-Aug-2013 | 02:54 | x86 |
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
More Information
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates