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Cisco Bug: CSCum77865 - No NAT of GRE tunnel unless cef is disabled on lan interface

Last Modified

Mar 06, 2017

Products (1)

  • Cisco IOS

Known Affected Releases


Description (partial)

Symptom: A router configured to NAT an encrypted (IPsec) GRE tunnel source does not actually do the NATting unless CEF is disabled, that is, 'no ip route-cache cef' is configured on the LAN interface, where the data packets arrive that are being forwarded out through the tunnel.
Conditions: IP CEF switching (ip route-cache cef) is enabled on the LAN interface.
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