DHCP Lease renewal

in Genius Bar edited January 2014
Ok I got one for you geniuses out there. After applying the recent 7-14 Security update for 10.2 I started having problems keeping my IP via DCHP (we do NAT via Win2000 Server). I'd get an IP, but it would drop intermittantly like every few minutes or so, get the same IP back, drop etc. Very annoying.

I'd had this happen to me before (after some OS X update) and the way I've solved it both times is to use the Cocktail application to renew my DHCP lease. Supposedly you can just go into Sys Prefs > Network > Network Port Configs and just toggle off your adapater, apply changes, then toggle it back on to renew a lease, but this never fixed anything for me. For some reason Cocktail does.

So my question is, how does Cocktail renew DHCP leases differently from toggling your Network Port Configs on/off? Also any ideas why I was having problems keeping my IP active in the first place?


  • Reply 1 of 5
    dviantdviant Posts: 483member
    hrm maybe I spoke too soon. I still seem to be having intermittant probs. Will post back if I find any solid answers/solutions.
  • Reply 2 of 5
    escherescher Posts: 1,811member

    Originally posted by dviant

    Will post back if I find any solid answers/solutions.

    Please do, dviant. The IT people at my university are incompetent and anti-Mac. One of the reasons they give is that the Macs, running OS 9.x, grab a DHCP IP and won't release it, which creates problems. Automatic lease-renewal is a possible answer, but those morons won't do anything (i.e. the Macs will be useless) unless I walk them through any solution.

  • Reply 3 of 5
    interesting ... i have started to experience a similiar prob (i think) .... my old DSL connection was always on ... no probs. I have moved and now use a cable connection...

    i lose my internet connection if it is idle for an extended period (hour or so) ... i have to restart the airport to get it up again.

    any suggestions ?
  • Reply 4 of 5
    escherescher Posts: 1,811member

    Originally posted by KingOfSomewhereHot

    any suggestions ?

    Using a router that can keep your connection alive should help. With the router taking care of maintaining the connection, it doesn't matter what your ABS and computers are doing and whether they are on or off. I haven't tested this with a cable modem, but it has worked exceedingly well with my DSL line for the last three years. My router maintains the PPPoE connection and checks on it every 20 seconds. If the connection is dropped for any reason, the router reconnects within 20 seconds.

  • Reply 5 of 5
    dviantdviant Posts: 483member
    Yeah i think in the case of home dsl/cable connections the lease times are a few hours long. I see my DSL modem at home drop off and renew now and then.

    My problem with 10.2 at work may have just been as stupid as a bad ethernet cable. In addition to renewing leases with Coctail, repairing permissions with disk util, restarts and *replacing my cable* things are back to normal. I'm not sure what did it exactly, I was more frantic than scientific unfortunately. But it still seems awfully coincidental that it all started immediately after that 7-14 security update.


    Escher, here's an article that explains how to renew your lease in OS 9 but that doesn't solve your problem

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