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hi there, i am new to wireshark and as i was learning it, i noticed that my smc router is sending packets to itself every second. under the protocol column, wireshark shows 0xffff. not sure why this is happening but maybe someone can explain it to me? is this normal? thanks in advance for any explainations.

Ethernet II, Src: SmcNetwo_0e:46:12 (12:26:f3:0e:46:12), Dst: SmcNetwo_0e:46:12 (00:26:f3:0e:46:12)

Destination: SmcNetwo_0e:46:12 (00:26:f3:0e:46:12) Address: SmcNetwo_0e:46:12 (00:26:f3:0e:46:12) .... ...0 .... .... .... .... = IG bit: Individual address (unicast) .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)

Source: SmcNetwo_0e:46:12 (12:26:f3:0e:46:12) Address: SmcNetwo_0e:46:12 (12:26:f3:0e:46:12) .... ...1 .... .... .... .... = IG bit: Group address (multicast/broadcast) .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default) Type: Unknown (0xffff)

Data (46 bytes) Data: 802814180580040000000000000000000000000000000000...

asked 18 May '11, 21:29

learner's gravatar image

learner
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How very interesting. If a person constantly talks to himself he will soon be committed.

The packets that you see are most likely the SMC way to identify a loop caused by 2 ports connected to each other.

Other vendors implement loop detection in one way or other. For example, Wireshark nicely decodes the Loop packets send by Cisco switches. The vendor independent feature would be the Spanning Tree Protocol or Rapid Spanning Tree.

Happy learning!

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answered 19 May '11, 03:16

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packethunter
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accept rate: 8%

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question asked: 18 May '11, 21:29

question was seen: 4,448 times

last updated: 19 May '11, 03:16

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