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Using ARP to kill idle connections

azzeretti · 2013-08-02 14:26:09

I am building a custom Wifi solution for a client and bashing some solutions for disconnecting idle connections (without some extra involvement!). I am building this on an embedded linux device using iptables. iptables doesn't have any parameters for dealing with idle connections so I am doing a little lateral thinking.…

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02-08-2013 3:26pm

#1

azzeretti

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I am building a custom Wifi solution for a client and bashing some solutions for disconnecting idle connections (without some extra involvement!). I am building this on an embedded linux device using iptables. iptables doesn't have any parameters for dealing with idle connections so I am doing a little lateral thinking. The idea is, once a user has been authenticated, I drop them into an ipset group. I was thinking of using ARP and every x minutes running a script to check the contents of the ipset group, clearing the ARP cache on the linux server then doing an ARP lookup against all the IPs in the list. Any clients still connected will respond while the dead ones should let arp know. At this point I can just remove them from the ipset group.

My question is; does anyone see any practical issue with clearing the ARP cache on the linux box so often? Its not a switch (there is 2 interfaces WIFI/LAN) and I can't see why the cache won't just rebuild as the clients announce again. The network(s) will be fairly small too - max 15 clients.

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