Cisco VPN Client Sending but not receiving (IP Fragmentation)

Summary

IP Fragmentation will not allow traffic to decrypt. Sending but not receiving.

Body

If the statistics on your Cisco VPN client are showing a value for sending, but 0 for receiving,and Decrypted has a value of 0, this is a sign of IP Fragmentation.

To resolve, please adjust the MTU buffer Size of the packets.

 

Go to "C:\Program Files (x86)\Cisco Systems\VPN Client\SetMTU.exe"

Choose respective adapter (Cisco Adapter is usually Local Area Connection 2 but not always. You can verify in network and sharing center under "Change Adapter Settings" or CMD>control netconnections) MTU Options>Custom> edit value to 1208

 

https://www.cisco.com/c/en/us/support/docs/ip/generic-routing-encapsulation-gre/25885-pmtud-ipfrag.html#anc2

 

Details

Details

Article ID: 42249
Created
Thu 11/9/17 11:11 AM
Modified
Mon 5/7/18 3:47 PM