Security

Hi everyone:

Lately,a quite unique problem confused me pretty much.

Here is the scene.

SSID A,authenticate and encryption is wpa-tkip and wpa-aes.

Android phone connect to the ssid A,sometime It could get the right ip address and access the network normaly.

But sometime It could also get the right ip address ,but It couldn't access the network ,and in my Access Controller ,I can't see the Android phone's IP,however my dhcp server have give IP address to it.

And if my dhcp server give a defined static ip address to this andriod phone.It could acess the network normaly again.If I cancel wpa-tkip or wpa-aes,in the open enviroment.It could works well again.

The eviroment has other factory's device.Such as symbol, and this phone works well in the symbol's enviroment which have the same authenticate and encryption.

Above all,any help or suggestion will be appreciated.

What version of code?  If you do not put a static ip address on the android, can you try pinging it to see if it appears in the user table?

yeah.If I pinged it it can be pinged ,after that It can access the network.But I'm not very sure of it,cause I pinged it 3 times, It did work for 2 times.

by the way ,the static ip address is given by the dhcp server, I binded it in the dhcp server.

and the code, you mean andriod's code?

2.3

0.99.332.8

2.6.35-g7a8b6d0

2.51.1403.1

6.1.2.5

If you have firewall prevent arp spoofing on, try turning it off:

config t

no firewall prohibit-arp-spoofing

Is this feature is enabled in default？

Cause I didn't do this configure.

It is not enabled by default.  type "show firewall" to see if that is.

Is there only one android device that cannot connect?

Is there any other possible reason?

cause this function I didn't have that on.

And the android phone's owner is the chief administrator.I can't borrow it easily?

Zake,

I do not know what could be happening.  Did he try connecting the Android device using an Open network?  Does this only happen using encryption?

Yes.

And the firewall prohibit-arp-spoofing is disabled.

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@zAke wrote:

Yes.

And the firewall prohibit-arp-spoofing is disabled.

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Are you saying it still happens on an open network?

no.

only using encryption

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@zAke wrote:

no.

only using encryption

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Sorry, that I don't have a solution.  Maybe someone can answer, or you can open a case...

As Colin mentioned, it will be worth opening a TAC case to troubleshoot this issue.

Meanwhile I wanted to draw your attentione to the some of the Androide related issues found by Princeton. I am not sure whether it is completely related to the issue you are describing or not, but I would say worth going throught this link once. :)

Link:

http://www.net.princeton.edu/android/android-stops-renewing-lease-keeps-using-IP-address-11236.html

Summary of the Android related issues found at Princeton :

Issue 1

After the lease has expired, the device continues using the IP address.

That is, it continues to respond to ARP Requests, claiming to own that IP address. It responds to ICMP Echo Request for that IP address. It responds to UDP and TCP traffic sent to that IP address. It initiates traffic to the Internet from that IP address.

Issue 2

Sometimes the malfunctioning device exhibits this issue in addition to issue #1.

While the device is continuing to use the IP address after the lease has expired, sometimes it unicasts DHCPREQUEST packets to the DHCP server for that lease, asking to renew the lease. It may do this for a few minutes, or for hours.

Issue 3

Sometimes, the device continues (or resumes) using the IP address from the old expired lease as well. That is, the device is now using both IP addresses simultaneously. (It answers IP ARP Request packets for both IP addresses.)