networking says obtaining ip never gets one

unix1adm

Member
May 20, 2011
89
1
My A500 was working fine up to a few days ago. Now it just says obtaining ip. Never seems to get one. Rebooted and re-added the network still nothing.


I am running 3.2 kernel 2.6.36.3+


Any thoughts?
 

Icebike

Senior Member
Apr 28, 2011
1,523
186
other people are connected fine. Not an issue with my router.

Don't be so quick to reject advice. Routers can get stuck on some devices as well.
Go into wifi settings and tell it to forget your router, then wait till it finds the router again and
enter your passphrase again. ONLY pick from the list of routers, don't go the "add wifi network" method.

If that does not work, Straighten a paper clip and wait till it says obtaining an ip and use the
paperclip to reset the tablet while it tries to obtain an ip the second time.
 

unix1adm

Member
May 20, 2011
89
1
now it seems like i cannot select teh networks int he Wi-Fi networks screen. it just locks up and cannot modify the settings.
 

unix1adm

Member
May 20, 2011
89
1
Don't be so quick to reject advice. Routers can get stuck on some devices as well.
Go into wifi settings and tell it to forget your router, then wait till it finds the router again and
enter your passphrase again. ONLY pick from the list of routers, don't go the "add wifi network" method.

If that does not work, Straighten a paper clip and wait till it says obtaining an ip and use the
paperclip to reset the tablet while it tries to obtain an ip the second time.

what will the paperclip do? reset just the wifi? I dont want to reset the tablet to factory defaults or something like that.

Well i tried the paperclip method and that did nto work. it did say authenticating for a moment but niw its just saying obtaining ip...
 
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Icebike

Senior Member
Apr 28, 2011
1,523
186
It will reset (reboot) the device.
Like Ctrl-Alt-Delete.

It won't reset to factory, and it has been known to solve the obtaining ip loop in past releases. Sometimes you have to try it a couple times.

Sometimes going somewhere else (different wifi) then coming back to your wifi will help. McDonalds, Public Library, Friends house, etc.
 

Douvie

Senior Member
Jun 10, 2011
1,030
71
other people are connected fine. Not an issue with my router.
The A500 is probably selecting an IP that is already in use. Get your tablet to forget the connection to your router/modem connection the IP issued to your tablet. Then go into the Wifi section and get it to to find a new IP address (force it to pick another address). Do what Icebike suggests go to another wifi point and see if the tablet will pick-up a new network with IP. If that works then it is your router.
 

Icebike

Senior Member
Apr 28, 2011
1,523
186
The A500 is probably selecting an IP that is already in use.

This is especially true if the OP went thru the manual assigning of IPs.
Often people think this is the way to go rather than figuring out why their DHCP server built into their router does not work.

Once you go down the road of manually assigning IPs its a never ending nightmare.
With any router manufactured after 1995, there is never a reason to use manually assigned static IPs.
They all support router reservations, so that specific machines like printers etc will always get the same ip.

ALSO, be aware that the Acer supports 802.11n on the 2.4ghz band only, it does not have a dual band
capability for 802.11n, so if your router tries to force clients to the 5ghz band after they connect
you will have to shut that feature off. I doubt this is the problem that the OP had, because they
said it was working previously.

Some routers come out of the box with a very small subnet defined. Some as low as 5 devices.
Add a few laptops, cell phones, and printers, xBoxs, and you run out. There is no penalty to
allowing a hundred two hundred units in the subnet. (255.255.255.0)
 

Chasmanian

Member
Aug 23, 2011
8
0
Another option to try is changing your dhcp lease time. It should be in your router's options. It's likely that an infinite lease time is interpreted by the tablet as extremely short rather than extremely long- forcing it to constantly renew its IP address. I changed mine to a week and haven't had the problem since. Good luck!
 

Douvie

Senior Member
Jun 10, 2011
1,030
71
Another option to try is changing your dhcp lease time. It should be in your router's options. It's likely that an infinite lease time is interpreted by the tablet as extremely short rather than extremely long- forcing it to constantly renew its IP address. I changed mine to a week and haven't had the problem since. Good luck!
Yep another very good suggestion. I believe Iceike has given a extremely good explanation.
 

Icebike

Senior Member
Apr 28, 2011
1,523
186
One more point on this lease time topic, then I'll quit, I promise..... :p

There is no advantage to a real long lease.
Anything over a day is overkill. It costs like 500 bytes total in back and forth packets to renew a lease.

Short leases (less than an hour) are often uses in real busy networks with lots of people coming and going,
such as at Starbucks and Public Libraries. There is no sense tying up an IP when the customer has left
the building.

Your phone or tablet will renew its lease each time the wifi comes on. (If it ever goes off - which mine never does),
as well as when ever the lease expires. Happens totally in the background, and won't interrupt any work in progress.

The router will not assign that IP to any other device even after the lease expires UNTIL IT HAS TO.
(Such as when it runs out of unused IPs).

DHCP servers use a "Least recently used" algorithm when assigning expired IPs to different devices.
So your tablet could be off for days, and when you come back and fire it up it will most likely get the
same IP. It logs them by your mac address.

The router looks up an ip from its list of free ips.
Then the router first pings that ip and if that ping is not returned, it assigns it.
If the Ping IS returned, it knows that someone usurped and IP, and it works around it.
(This is why manually assigned static IPs can live on the same network with DHCP assigned IPs, - because the router works around usurped IPs).

I've never seen any router hand out an IP that was already in use, and turned on. Just doesn't happen.

They might hand out an IP that was long disused by a device that is not on the net (turned off).
Then that guy fires up his manually assigned IP device and collisions happen, and all hell breaks loose, and somebody has to move but it won't be the manually assigned guy, so your tablet gets kicked off.

Routers should handle this, but I've seen some cheep routers get totally messed up with phones and
tablets coming and going all day long. Set your wifi disconnect policy to NEVER, and its much more
reliable.

Sometimes router get so messed up power-off, reboot is a good idea.
 
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Douvie

Senior Member
Jun 10, 2011
1,030
71
Good lord no...don't stop. We all hang out for words of wisdom which drop from your finger tips Icebike. You usually keep us well informed.
 

unix1adm

Member
May 20, 2011
89
1
Thank you for all that info. We are set up as dhcp not fixed. I did try the reset still did not work.

So i took a walk over to the network guys office (he has been out for a few days) and he could not get on either. So it looks like the router may be down.
He is going to reset and get back to me.

Its strange. the router is acting like its up but maybe someone changed a configuration and kicked us off.
Ill report back when they resolve it.

Again thanx for all the great info and please dont stop. :)
 

Douvie

Senior Member
Jun 10, 2011
1,030
71
Thank you for all that info. We are set up as dhcp not fixed. I did try the reset still did not work.

So i took a walk over to the network guys office (he has been out for a few days) and he could not get on either. So it looks like the router may be down.
He is going to reset and get back to me.

Its strange. the router is acting like its up but maybe someone changed a configuration and kicked us off.
Ill report back when they resolve it.

Again thanx for all the great info and please dont stop. :)
Yeah, sounds like the culprit to me. Maybe you 've got some IT wannabe, like the boss who has admin access, or at least someone like that who's got admin rights and is stuffing it up for everyone else.

I see IT guys who are IT WANNABEs all day in my job. Then once in a while you come across someone who really knows his system and really makes your day.
 
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