Issues with sleep, wifi and IP addresses

Tumbleweed666

macrumors 68000
Original poster
Mar 20, 2009
1,656
59
Near London, UK.
This morning after waking from sleep, my iMac (10.8.5) was saying there was another device on the network using the same IP. I presume this was because whilst it was asleep, DHCP leases got renewed so another device got assigned the IP the Mac was using.
Annoying in that I'd have expected it to be able to deal with this by just asking for a new IP after waking up.

What was much worse was that none of "renew lease", switching wireless off and on, and even rebooting didn't fix this, it was still "clinging" to the old IP.

In the end I assigned one manually way above the normal numbers, and after that, have even got it back on its "old" one, and its been fine.

Now I have assigned a manual number at the start of the range and set DHCP on the router to assign above that, but has anyone else seen this issue, was it just a glitch, or shall i leave it like this? I had only recently allowed it to sleep, generally it never sleeps (just the display)
 

r0k

macrumors 68040
Mar 3, 2008
3,610
73
Detroit
This morning after waking from sleep, my iMac (10.8.5) was saying there was another device on the network using the same IP. I presume this was because whilst it was asleep, DHCP leases got renewed so another device got assigned the IP the Mac was using.
Annoying in that I'd have expected it to be able to deal with this by just asking for a new IP after waking up.

What was much worse was that none of "renew lease", switching wireless off and on, and even rebooting didn't fix this, it was still "clinging" to the old IP.

In the end I assigned one manually way above the normal numbers, and after that, have even got it back on its "old" one, and its been fine.

Now I have assigned a manual number at the start of the range and set DHCP on the router to assign above that, but has anyone else seen this issue, was it just a glitch, or shall i leave it like this? I had only recently allowed it to sleep, generally it never sleeps (just the display)
I was getting these errors from time to time. It took quite a while before I found the culprit. It was a Dlink AP1522 access point. It was "automatically" switching from Access Point to Bridge mode. This created a loop and several computers on our network were reporting duplicate IP addresses. I've updated the firmware on my Dlink access point and convinced myself that even in a power failure it won't wake up thinking it's a bridge and I haven't seen the duplicate IP message since.
 

morespce54

macrumors 65816
Apr 30, 2004
1,331
11
Around the World
As mentioned above, It's likely related to the router (and router settings) rather than the Mac. Normally, you shouldn't have to enter a IP manually on the Mac (unless you have specific needs).

Have you install a new router or change some settings from your old one?

You can try to update the firmware (if available) or unplug/reset your router to see if that helps.


I have been having these issues (among others) since a few weeks but that's likely because I've change WAP2 setting on my 2002 router... Obviously, no firmware is available for this one. Time to look for a more recent router for me I guess! My dear beloved DLINK...
 

Tumbleweed666

macrumors 68000
Original poster
Mar 20, 2009
1,656
59
Near London, UK.
Well the router has been there several weeks and it comes from the ISP and as it's connected to a fibre system I'm not very keen to start monkeying with it in case I brick it, indeed I am pretty sure I shouldn't be doing anything with it along the lines of updating etc, under whatever contract I have with the ISP, I think it manages that itself. I'll check into that though.

So you think the router has just handed out the same IP to two devices?
Makes sense as to why even a reboot didn't fix it, against that is that every other device that I connected just got assigned the next number up, it's only this one that had the issue.
Everything is wifi connected so there is nothing special about the iMac from a connectivity POV it's just another device.
 
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