Cisco DTP negociator
From IPFlow Netflow Collector
This tool permits a user with a Linux box to negociate a trunk (802.1Q or ISL) with a Cisco switch running DTP (Cisco Dynamic Trunk Protocol).
In order to be useful, it also downloads the VLAN database using the Cisco VTP protocol (note: only working with 802.1Q trunks now).
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Example
vortex:~/dtp# ./ipflow dtp eth1 000d.1234.5678 dot1q serv_mgr: unable to open file './protocols.txt' (No such file or directory) serv_mgr: unable to open file './services.txt' (No such file or directory) IPFlow Collector - Release 0.49.7-X3-24 23-Mar-05 (BETA) Compiled at Mar 31 2005 02:18:58 by Christophe Fillot (cf@utc.fr) IPFlow Dynamic Trunk Protocol negociator started. DTP: VTP domain name is 'TEST'. VTP: Starting timer to get VLAN list... VTP: Sending Advert-Request frame to obtain VLAN list... Link is detected as 802.1Q. VTP: Sending Advert-Request frame to obtain VLAN list... VTP VLAN List (configuration revision 112) : 1 default active 2 ENGINEERING active 3 MARKETING active 4 DMZ1 active 5 DMZ2 active 1002 fddi-default active 1003 trcrf-default active 1004 fddinet-default active 1005 trbrf-default active
The program needs to run continously to maintain the trunk.
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Command Line Syntax
- The first parameter (here "eth1") is the ethernet interface connected to the switch.
- The second parameter ("000d.1234.5678") is the ethernet address to use to communicate with the switch.
- The third parameter is the trunk type and can be : "dot1q", "isl" or "none". If you specify "none", the switch port will become an access port.
Remark: you need root access since this tool uses raw ethernet sockets.
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How to use it ?
The Linux kernel supports 802.1Q encapsulation in software, even if your network card doesn't support it in hardware. You can easily create sub-interfaces with the "vconfig" utility.
