land protection for cisco

From: Stefan Stefanov (stefanat_private)
Date: Fri Nov 21 1997 - 07:01:28 PST

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    hi.
    
    Here is a simple protection against the land stuff for the cisco's. It's a
    extended ip access list that should be put on all the intefaces on the
    box.
    
    Extended IP Access list 105
    deny tcp host 111.111.111.111 host 111.111.111.111
    permit ip any any
    
    where 111.111.111.111 is the interface's ip address. This should be put
    as
    an input access-group.
    
    Or if you don't get it here's what to type on your cisco's console.
    
    rtr#config terminal
    rtr(config)#access-list 105 deny tcp 111.111.111.111 0.0.0.0 111.111.111.111 0.0.0.0
    rtr(config)#access-list 105 permit ip any any
    rtr(config)#interface ethernet 0
    rtr(config)#ip access-group 105 in
    rtr(config)#exit
    rtr(config)#interface serial 0
    rtr(config)#ip access-group 105 in
    
    and so on for the rest of the interfaces... Replace 105 with a free
    extended access-list number.
    
    I have tested it on our cisco 2511 and it works just ok.
    
    Best regards, Stefan Stefanov.
    
    WWW:    http://www.bis.bg/~stefan
    E-mail: stefanat_private
    



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