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Windows 7 Jumbo Frames > Only working one direction?

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Last Modified: 2014-08-16
Two computers (192.168.0.2 w/MTU 7K and 192.168.0.4 w/MTU 9K) are setup for jumbo frames.  The first (192.168.0.2 ) can ping itself and the other with jumbo frames.  The second (192.168.0.4) can ping itself with jumbo frames but fails when pinging the other.

What's my problem?

Attached is output from second box, (192.168.0.4).

ScreenShot028.png
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Top Expert 2014

Commented:
I would double check to verify you have jumbo frames enabled and set correctly.  You can ping your address with frames larger than 1500 bytes even with jumbo frames not enabled.

Issue the command:

netsh interface ipv4 show interfaces

to see what the MTU is set to.

Author

Commented:
Here's the details on the second box:
C:\Users\johndoe>ipconfig

Windows IP Configuration


Ethernet adapter Local Area Connection:

   Connection-specific DNS Suffix  . :
   IPv4 Address. . . . . . . . . . . : 192.168.0.4
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . : 192.168.0.1

Tunnel adapter isatap.{8C68870B-A7F2-433A-88B4-3B1E175F48DD}:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :

Tunnel adapter Teredo Tunneling Pseudo-Interface:

   Connection-specific DNS Suffix  . :
   IPv6 Address. . . . . . . . . . . : 2001:0:5ef5:79fb:204d:34f4:3f57:fffb
   Link-local IPv6 Address . . . . . : fe80::204d:34f4:3f57:fffb%13
   Default Gateway . . . . . . . . . : ::

C:\Users\johndoe>
C:\Users\johndoe>
C:\Users\johndoe>
C:\Users\johndoe>netsh interface ipv4 show interfaces

Idx     Met         MTU          State                Name
---  ----------  ----------  ------------  ---------------------------
  1          50  4294967295  connected     Loopback Pseudo-Interface 1
 11          10        1452  connected     Local Area Connection


C:\Users\johndoe>

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Remember I can successfully ping the second box (192.168.0.4) with Jumbo Frames from the first box (192.168.0.2) per below:
C:\Windows\system32>ipconfig

Windows IP Configuration


Ethernet adapter Local Area Connection:

   Connection-specific DNS Suffix  . :
   IPv4 Address. . . . . . . . . . . : 192.168.0.2
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . : 192.168.0.1

Tunnel adapter Local Area Connection* 9:

   Connection-specific DNS Suffix  . :
   IPv6 Address. . . . . . . . . . . : 2001:0:9d38:90d7:1408:2a:3f57:fffd
   Link-local IPv6 Address . . . . . : fe80::1408:2a:3f57:fffd%11
   Default Gateway . . . . . . . . . : ::

Tunnel adapter isatap.{593FD5C6-7B21-4621-AA8A-40106436590A}:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :

C:\Windows\system32>ping -f -l 5000 192.168.0.4

Pinging 192.168.0.4 with 5000 bytes of data:
Reply from 192.168.0.4: bytes=5000 time<1ms TTL=128
Reply from 192.168.0.4: bytes=5000 time<1ms TTL=128
Reply from 192.168.0.4: bytes=5000 time<1ms TTL=128
Reply from 192.168.0.4: bytes=5000 time<1ms TTL=128

Ping statistics for 192.168.0.4:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 0ms, Average = 0ms

C:\Windows\system32>

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Commented:
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Author

Commented:
That fixed it!  I didn't know the MTU on the operating system had to be set - I thought changing the MTU on the hardware would cause the OS to change too.  Thanks so much!!

http://answers.microsoft.com/en-us/windows/forum/windows_7-networking/how-do-i-change-the-mtu-setting-in-windows-7/ec01f5d0-7082-4a9d-97b5-1d1dccb121d2
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Top Expert 2014

Commented:
Glad to have helped.

Setting it on the hardware allows inbound frames to be larger, but outbound frames are controlled by the OS.
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