I have a VPN tunnel between an 871 and 877, the tunnel seems to be fine, but checking the tunnel using SDM shows an error.
Checking the tunnel status... Up
Encapsulation :330231
Decapsulation :393226
Send Error :7939
Received Error :0
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A ping with data size of this VPN interface MTU size and 'Do not Fragment' bit set to the other end VPN device is failing. This may happen if there is a lesser MTU network which drops the 'Do not Fragmet' packets.
1)Contact your ISP/Administrator to resolve this issue. 2)Issue the command 'crypto ipsec df-bit clear' under the VPN interface to avoid packets drop due to fragmentation.
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Are the send errors anything to worry about?
Do I need to issue the 'crypto ipsec df-bit clear' on the routers?
Any info would be much appreciated.
Thanks
Gareth
