strange log

[Emilio Casbas <ecasbas () unav es>]

Hi,

We've seen  in the firewall's log of transparent proxy this messege from 
different ips repeteadly :

Apr 21 21:28:55 moria kernel: TCP: Treason uncloaked! Peer 
external_ip/80 shrinks window 1466359669:1466360884. Repaired.

We've googling, but we dont know if is an attack or a bad negotiation.
Any suggestion?

Thanks
Emilio C.

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