Why would this happen in my wireless lan? Apple devices not connecting!

[iamgenius]

Hello folks. I just want to share an issue with my wifi that I thought is interesting and some of you can shed some light to help me.

I have this very nice Netgear WNDR3700v3 wireless router which I like and has served me well since I first had it. It is set on 192.168.1.1 and DHCP is on and distributing IP's as usual.
Sometimes my ipad's and my iphone's (and some android devices maybe) will successfully connect but there will be no internet access. If I go check the details in the device, I'll see that it acquired an ip address like 192.168.0.98, which explains why there is no internet connectivity(different subnet). If I switch to static configuration and force it to use an ip address outside of the DHCP range but in the same subnet and input the subnet mask & default gateway manually, it will just work.

Why isn't DHCP distributing IP's correctly?

I have a relatively big two story house, and this is how it is setup:

The main wireless router is in a room upstairs. Through power-line networking, internet reaches downstairs and get distributed via an AP which is enough because we are mostly upstairs. To cover the rest of the horizontal space upstairs, I'm using two AP's which are set as repeaters and one is setup as a range extender.

The problem is that it just works, but I sometimes face the above mentioned problem which I can't really identify why.

So why do you think this would happen? Any clues?

 

[AnonymouseUser]

Changing the value of the RIP Version from Disabled to RIP_2B under the LAN Setup section fixed the issue for me. Hope this helps.

More info here.

 

[VirtualLarry]

More info here.

Can someone explain to me in simple terms how RIP is related to DHCP as a protocol? I thought RIP was a routing protocol like BGP, to distribute and announce routes between routers. How is this required for a functioning DHCP server?

 

[dave_the_nerd]

I have a similar symptom, but it effects all network devices, not just Apple.

I have a wifi bridge for my printer, and sometimes it goes stupid and starts being a dhcp server.

 

[iamgenius]

Interesting. I thought I was doing something wrong. I'll try this and report back.

Thanks.

 

[iamgenius]

It just happened again. Even after changing the value, I still get my iphone connected with an ip address like 192.168.0.80 with the default gateway being 192.168.0.1.

I wonder if channel selection has anything to do with it. They are 11 channels and I know that channels 1, 6, and 11 are non-overlapping. Now if you have two access point which are close to each other, should they be using different channels??

 

[dave_the_nerd]

The APs should automatically switch between channels to not trip on each other, yes. (Reboot may be required.)

If your DHCP server is distributing IPs outside of its network range, than your iPhone isn't getting an IP from that DHCP server. Looks like you've got a rogue.

 

[azazel1024]

The APs should automatically switch between channels to not trip on each other, yes. (Reboot may be required.)

If your DHCP server is distributing IPs outside of its network range, than your iPhone isn't getting an IP from that DHCP server. Looks like you've got a rogue.

Are both your APs acting as DHCP servers? Are they on different IP ranges?

Everything should be on the same 192.168.x.1-254 range. Is there any chance your phones are connecting to a neighbors network by accident? Or some other open wifi network that you have the name entered in for? Any chance someone has an identical name to your network? Try InSSIDer or other wifi snooping program to see how many and what names there are for wifi access points around you. If you see a bunch of APs with the same name as your wifi network...ya know.

 

[iamgenius]

The DHCP server is only on in the main wireless router which you can see in the OP. All other wireless devices are either set as repeaters or range extenders. And NO, I'm not connecting to a neighbors network. I actually always change my SSID name. The closest neighbor is too faraway for a wifi signal to get picked up. There is no need to use a program to check, because I'm 100% sure I'm connecting to my AP. The reason being(like I said in the OP) that switching to static will get me online, and it is the same AP with the same unique name I'm using.

Told you it is weird, I'm puzzled myself.

 

[dave_the_nerd]

Bet you an internet that one of your repeaters/range-extenders is misconfigured.

If your phone was getting an IP from itself, it'd be 169.x.x.x (self-assigned.) It's getting that 192.168.0.x IP from somebody, and if you're on the right WiFi network, then it's from somebody on your LAN. It's really that simple.

So start turning things off and on again until the problem stops.

 

[iamgenius]

Bet you an internet that one of your repeaters/range-extenders is misconfigured.

If your phone was getting an IP from itself, it'd be 169.x.x.x (self-assigned.) It's getting that 192.168.0.x IP from somebody, and if you're on the right WiFi network, then it's from somebody on your LAN. It's really that simple.

So start turning things off and on again until the problem stops.

Well, everything in the LAN is in the 192.168.1.x subnet. How can it be from somebody on the LAN? Clients don't distribute IP addresses.

Also, the problem doesn't happen all the time, so it will be really hard to tell even if I disconnect or turn off devices.

Thanks.

 

[Pandasaurus]

I think you missed the point. If your (wireless only) devices are getting IP's from DHCP, but not in the same subnet as your DHCP server (and we assume none of your other AP's are mis-configured), by far the two most likely options are either a rogue AP spoofing your SSID, or a rogue device on your network acting as a DHCP server. I suppose there is some possibility of a very unusual software glitch in either one of your AP's or *all* of your wireless clients causing them to use addresses outside of the subnet the DHCP server is in, but... That seems pretty unlikely to me.