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Kindle WiFi IP Stack Error

By charleytoo ·
I thought I would post this to see if others have experienced the problem and to provide a workaround. The issue is that the Kindle will fail to connect to the Internet when the DNS servers are in the same subnet as the Kindle. Here is my experience...

We recently received a new Kindle WiFi (the $139 version). It would not connect to our WiFi network. Other computers and devices could connect and access the Internet. After several attempts, including completely disabling WiFi security in the access point, we had no luck. To test the Kindle we took it to Starbucks -- it worked fine there.

Back home. We didn't get any useful help from Amazon's Kindle support so I started digging through network logs. It turns out the Kindle was actually connecting. The DHCP server log showed it getting an IP address (192.168.1.93) along with the gateway (192.168.1.1) and DNS server addresses (192.168.1.5 and 192.168.1.6).

I put a network sniffer between the WiFi access point and the network. The DHCP packets showed the Kindle connecting. After the Kindle connected, it used ARP to obtain the MAC address of the gateway. Then it started flooding the network with DNS requests for dns.kindle.com and a server in the cloudfront.net domain. There were no reply packets from the DNS servers.

Our DNS servers were working for other devices but had no log entry for the Kindle's request. A close inspection of the Kindle DNS request packets revealed that it was sending them to the correct IP addresses for the DNS servers but was directing them to the MAC address of the gateway rather than the MAC addresses of the DNS servers. Since the packets could not be routed to the Internet, the gateway dropped them.

It appears that the Kindle stack implementation assumes that all DNS packets should be sent to the gateway. This works in nearly all home networks and most public WiFi hotspots because the wireless router is either a proxy for DNS or the DNS servers are located on the Internet side of the WiFi router. Many business networks would have local DNS servers as described here.

My workaround was to manually configure the Kindle to use an external DNS server provided by our ISP. You could also use one at openDNS. The configuration can be set through the Kindle keyboard or DHCP can be configured to deliver the settings based on the Kindle MAC address.

Hopefully Amazon will fix this with a software update since the workaround can only be used when you know a safe IP address to manually configure for the Kindle.

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So, the packets don't go to the DNS servers to be forwarded?

by seanferd In reply to Kindle WiFi IP Stack Erro ...

Why, if you can configure external DNS addresses, can you not configure LAN DNS addresses? It ignores these in favor of the default gateway address? That is ridiculous and deeply wrong.

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You can configure them but..

by charleytoo In reply to So, the packets don't go ...

the Kindle doesn't check to see that they are on the LAN before sending to the gateway. After reading your question I wondered if the Kindle would access any LAN device other than the gateway. Using Kindle's browser, I could access a web server on the LAN by entering its IP address. Ironically the web server is on the same host as the local DNS that was ignored.

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fixed in 3.0.3

by jeffreyhmcclure In reply to Kindle WiFi IP Stack Erro ...

I had this same problem with my new Kindle 3 and reported it to Amazon, including Wireshark logs, here: http://www.amazon.com/tag/kindle/forum/ref=cm_cd_notf_thread?_encoding=UTF8&cdForum=Fx1D7SY3BVSESG&cdPage=1&cdThread=Tx3O1BYKVMLUEYU

Anyway, I recently updated my Kindle to the "early preview" 3.0.3 software, and this problem appears to be fixed. The download is available here:
http://www.amazon.com/gp/help/customer/display.html/ref=hp_navbox_top_kindlelg?nodeId=200529700

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