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I'm having issues with my C3200 that I suspect are the same as those with the TP-Link routers listed below. Can anybody verify that is the problem and if so what is the fix? Hi :-)>> The UDP checksum for outgoing L2TP datagrams seems to be broken.> It has been tested with TP-LINK's WR842n, WDR3600, and WDR4300.> On two normal Linux computers it's working.>> We've tried disabling UDP offloading using ethtool without success.>> Is there any way we can make OpenWRT emit the datagrams with the> checksum in place?>> This shows up in Wireshark. The first two datagrams are being received> on the other side. The ones after the l2tp aren't.>> #this is received on the other end. normal udp> 14.6944 UDP 575 52958 → 53201 Len=513> 14.8159 UDP 152 53201 → 52958 Len=90> #ip l2tp add tunnel tunnel_id 52958 peer_tunnel_id 53201 encap udp> local '2001:920:18ae:3:20b:c0ff:fe46:42b0' udp_sport 52958 remote> '2a03:b0c0:3:d0::bb5:6001' udp_dport 53201> 14.9130 UDP 184 52958 → 53201 Len=122 [ILLEGAL CHECKSUM (0)]> 15.3230 UDP 152 52958 → 53201 Len=90 [ILLEGAL CHECKSUM (0)]> 15.6929 UDP 184 52958 → 53201 Len=122 [ILLEGAL CHECKSUM (0)]> 15.8198 UDP 164 53201 → 52958 Len=102>> hoping somebody has an idea :-)You may want to apply this kernel patch: https://github.com/torvalds/linux/commit/018f8258582381bcce484312f0e9ec2970d0383e yousong