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Re: [lwip-users] win32 porting contrib: double IP address
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From: |
Giuseppe Modugno |
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Subject: |
Re: [lwip-users] win32 porting contrib: double IP address |
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Date: |
Thu, 9 Nov 2017 10:41:44 +0100 |
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User-agent: |
Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 |
Il 08/11/2017 16:34, Joel Cunningham ha scritto:
The ping works well if I launch "ping 192.168.1.156" command from
*another* computer on the same network.
You're most likely running into a checksum offload problem since you
can't contact the LwIP stack from the Windows host, but you CAN from
another machine. The Window's TCP/IP stack is going to use checksum
offloading for IPv4/UDP/TCP and during the transmit path, Winpcap will
capture them before they go to hardware (where checksum is added).
Then they will fail checksum validation in LwIP and be discarded.
You can verify this easily by opening up wireshark and capturing on
the interface. Wireshark (also using winpcap) will capture the
packets at the same point and you can verify the checksum is missing.
You're right.
If this is the case, you can disable checksum offloading in Windows
for TX.
What is the procedure to disable checksum offloading in Windows for TX?