Re: SYN/ACK to port 53

From: Ryan Russell (ryanat_private)
Date: Thu May 24 2001 - 13:36:57 PDT

  • Next message: Steve Halligan: "RE: SYN/ACK to port 53"

    On Thu, 24 May 2001, DeCamp, Paul wrote:
    
    > A SYN/ACK packet is sent to TCP port 53.  No SYN was sent from our system.
    > The SYN & ACK sequence numbers appear to be random, but the ACK is always 1
    > less than the SYN.  Our system responds with a RST to the ACK.
    
    Exactly what you would expect to see if someone sent them a spoofed packet
    claiming to be from your IP address, source port 53.  What are the other
    port numbers?
    
    Now why someone would do that, I can't say.  There are some passive
    fingerprinting techniques this might apply for..
    
    					Ryan
    



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