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N66U and Spanning Tree...

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sfx2000

Part of the Furniture
Interesting observation on Wireshark...

Have a neighbour with a new N66U AP - nice unit :)

The box is configured with WPA2-PSK - but in a wireshark capture, something I noticed is that the box is sending out STP frames, and more importantly, sending them out TKIP, not AES.

So a couple of questions:

1) Why is the N66U sending out STP frames? Useful perhaps in Mesh WiFi networks, but useless in a home environment
2) Why is a TKIP vector present in the STP frame?

packet dump link (some vals changed to protect the innocent):

https://dl.dropbox.com/u/2181814/N66u_STP_TKIP.txt

Bug? Feature?
 
Last edited:
Interesting observation on Wireshark...

Have a neighbour with a new N66U AP - nice unit :)

The box is configured with WPA2-PSK - but in a wireshark capture, something I noticed is that the box is sending out STP frames, and more importantly, sending them out TKIP, not AES.

So a couple of questions:

1) Why is the N66U sending out STP frames? Useful perhaps in Mesh WiFi networks, but useless in a home environment
2) Why is a TKIP vector present in the STP frame?

packet dump link (some vals changed to protect the innocent):

https://dl.dropbox.com/u/2181814/N66u_STP_TKIP.txt

Bug? Feature?

This is a good find sfx, was this unit running the stock Asus firmware?
 
I turned STP off because my understanding of it is that when I just have one router it isn't needed. When I had a WDS system with 3 routers I did enable it.

Now I guess doing so may not be a bad idea for other reasons.
 
I turned STP off because my understanding of it is that when I just have one router it isn't needed. When I had a WDS system with 3 routers I did enable it.

Now I guess doing so may not be a bad idea for other reasons.

Don't need STP frames for WDS - different layer... STP is layer 3, WDS is layer 2...
 
Bumping the thread - this is likely a security issue - if the primary is WPA2-AES, the STP frames being sent out TKIP is not very smart.

IEEE 802.11 Data, Flags: .p....F.
Type/Subtype: Data (0x20)
Frame Control: 0x4208 (Normal)
Version: 0
Type: Data frame (2)
Subtype: 0
Flags: 0x42
.... ..10 = DS status: Frame from DS to a STA via AP(To DS: 0 From DS: 1) (0x02)
.... .0.. = More Fragments: This is the last fragment
.... 0... = Retry: Frame is not being retransmitted
...0 .... = PWR MGT: STA will stay up
..0. .... = More Data: No data buffered
.1.. .... = Protected flag: Data is protected
0... .... = Order flag: Not strictly ordered
Duration: 0
Destination address: Spanning-tree-(for-bridges)_00 (01:80:c2:00:00:00)
BSS Id: 30:85:a9:xx:yy:zz (30:85:a9:xx:yy:zz)
Source address: 30:85:a9:xx:yy:zz (30:85:a9:xx:yy:zz)
Fragment number: 0
Sequence number: 292
TKIP parameters
TKIP Ext. Initialization Vector: 0x00000007F200
Key Index: 2
Data (46 bytes)

0000 fa 08 9d 79 79 c9 ac 3f 21 2d 47 7d bc 46 50 97 ...yy..?!-G}.FP.
0010 25 02 e4 4d f1 d0 7a c8 34 07 86 34 f7 ad 5e eb %..M..z.4..4..^.
0020 84 2d 30 c7 a2 a8 38 33 5e 96 24 46 c5 8f .-0...83^.$F..
Data: fa089d7979c9ac3f212d477dbc4650972502e44df1d07ac8...
[Length: 46]
 

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