Default setting for Cisco 2950 Switch

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May 12th, 2008
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Hello, I was wondering what the default administrative mode is on the switch interface ports?

Do they form trunks automatically when connected to other switches?

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Overall Rating: 5 (2 ratings)
JORGE RODRIGUEZ Mon, 05/12/2008 - 18:25
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default on switch with no configuration for all ports is vlan 1 including any gigabit uplink ports if any, no other configuration is set for any type of trunking unless it is manualy configured for trunking or dynamic trunking.



Nikos5555 Tue, 05/13/2008 - 00:19
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Is that correct? because that contradicts the other post.

JORGE RODRIGUEZ Tue, 05/13/2008 - 07:58
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In my experience for a switch that comes with no configuration I have always manualy make a switchport wether is a normal 10/100/1000 access port or gigabit port to participate in trunking either dynamic or non-dynamic, whether this has changed that ports defaults to dynamic on all ports I am not aware of it.

The simplest way to find out would be to have your switch connect to another switch to see if it auto negotiates DTP.



I know it conflicts, but I asked the switch and it told me so

#sh ver

Cisco Internetwork Operating System Software

IOS (tm) C2950 Software (C2950-I6K2L2Q4-M), Version 12.1(22)EA10a, RELEASE SOFTWARE (fc2)

cisco WS-C2950-12 (RC32300) processor (revision B0) with 19918K bytes of memory.

Running Standard Image

12 FastEthernet/IEEE 802.3 interface(s)

#sh run int f0/1

Building configuration...

Current configuration : 33 bytes


interface FastEthernet0/1


#sh int f0/1 switchport

Name: Fa0/1

Switchport: Enabled

Administrative Mode: dynamic desirable

Operational Mode: down

Administrative Trunking Encapsulation: dot1q

Negotiation of Trunking: On

Access Mode VLAN: 1 (default)

Trunking Native Mode VLAN: 1 (default)

Voice VLAN: none

Administrative private-vlan host-association: none

Administrative private-vlan mapping: none

Administrative private-vlan trunk native VLAN: none

Administrative private-vlan trunk encapsulation: dot1q

Administrative private-vlan trunk normal VLANs: none

Administrative private-vlan trunk private VLANs: none

Operational private-vlan: none

Trunking VLANs Enabled: ALL

Pruning VLANs Enabled: 2-1001

Capture Mode Disabled

Capture VLANs Allowed: ALL

Protected: false

Appliance trust: none

#sh interfaces f0/1 trunk

Port Mode Encapsulation Status Native vlan

Fa0/1 desirable 802.1q not-trunking 1

glen.grant Tue, 05/13/2008 - 08:34
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He is correct , default is dynamic desirable so if you plug into a cisco switch on the other end and the port is set as desirable or auto it will form a trunk .

JORGE RODRIGUEZ Tue, 05/13/2008 - 08:36
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I guess jcoke is the winner then, new info learned ! and deserves a good rating.

Nikos5555 Wed, 05/14/2008 - 00:59
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Thanks for your efforts guys, really appreciate it!


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