BTW, there are some packets in the server capture (such as the first two) with an IP protocol type of 0xe0; any idea what they are? (There are also some SNAP packets with an OUI of 0x00000c, for Cisco, and a protocol ID of 0x2004; does anybody know what *those* are?)

Looks like Dynamic Trunking Protocol multicast
http://www.cisco.com/en/US/products/hw/switches/ps663/products_tech_note09186a0080094713.shtml


says:

Cisco has a reserved range of Ethernet MAC and protocol addresses as shown below. Each one will be covered later in this document, however, a summary is presented in the table below for convenience.

Feature SNAP HDLC Protocol Type Destination Multicast MAC

Port Aggregation Protocol (PAgP) 0x0104 01-00-0c-cc-cc-cc

Spanning Tree PVSTP+ 0x010b 01-00-0c-cc-cc-cd

VLAN Bridge 0x010c 01-00-0c-cd-cd-ce

Unidirectional Link Detection (UDLD) 0x0111 01-00-0c-cc-cc-cc

Cisco Discovery Protocol 0x2000 01-00-0c-cc-cc-cc

Dynamic Trunking (DTP) 0x2004 01-00-0c-cc-cc-cc

STP Uplink Fast 0x200a 01-00-0c-cd-cd-cd

IEEE Spanning Tree 802.1d N/A - DSAP 42 SSAP 42 01-80-c2-00-00-00

Inter Switch Link (ISL) N/A 01-00-0c-00-00-00

VLAN Trunking (VTP) 0x2003 01-00-0c-cc-cc-cc

IEEE Pause, 802.3x N/A - DSAP 81 SSAP 80 01-80-C2-00-00-00>0F

The majority of Cisco control protocols use an IEEE 802.3 SNAP enc

--
John McDermott
Writer, Educator, Consultant
[EMAIL PROTECTED]               http://www.jkintl.com
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