Unmanaged Cisco Switch Question

jem7sk

I have a Catalyst 3750 24 port switch. I'm using some cheap 8 port switch that I just connect to a managed Cisco network and everything works fine. I was under the impression that if I set the Catalyst to factory defaults it would just work like the cheap switch but that is not the case. Is there any way to make this happen? I need more ports for computers in this room. I've already restored the Catalyst to factory defaults and removed the previously configured Vlans but it will not pass traffic like the 8 ports switch.

mjsinhsv

Is the 8 port a switch or a hub?
When you connected the cisco 3750 to the managed network did you create a trunk port?

MTciscoguy

I was able to get one of mine working like a simple switch the other day, My 24 port 2950G, I simply plugged a cat cable from my internet router into port one and plugged a bunch of computers and network items into it and works like a charm.

jem7sk

mjsinhsv wrote: »

Is the 8 port a switch or a hub?
When you connected the cisco 3750 to the managed network did you create a trunk port?

It is a Freedom unmanaged or "dumb" switch. I did not create a trunk port... from my minimum study for CCENT I was under the assumption a Cisco switch would work right out of the box like I am wanting to do here. Just did the Factory Default restore on the switch and then deleted the VLAN configs like the instructions on Cisco's website.

jem7sk

MTciscoguy wrote: »

I was able to get one of mine working like a simple switch the other day, My 24 port 2950G, I simply plugged a cat cable from my internet router into port one and plugged a bunch of computers and network items into it and works like a charm.

I plugged in a cat 5 cable from the corporate network into my switch (tried various ports) and it blinks orange on my switch's side and green on the network switch's side. The clients cannot get DHCP information.

joelsfood

Lots of thigns it could be (STP comes to mind), which can be hard to tell without actually logging in and confirming.

Just out of curiousity, any reason you don't get rid of the 8 port switch and just plug everything into the 3750? Though, for regular home use, a 3750 is rather loud and large, particularly if you're just using a single VLAN, no management, etc.

Hondabuff

Do in order on the 3750 first and report back.

Switch>enSwitch#erase startup-config
Erasing the nvram filesystem will remove all configuration files! Continue? [confirm]
[OK]
Erase of nvram: complete
%SYS-7-NV_BLOCK_INIT: Initialized the geometry of nvram
Switch#delete vlan.dat
Delete filename [vlan.dat]?
Delete flash:/vlan.dat? [confirm]
Switch#erase startup-config
Erasing the nvram filesystem will remove all configuration files! Continue? [confirm]r
Switch#
Switch#reload
Proceed with reload? [confirm]

Priston

Is it a gig switch? Did you use a crossover or straight-through cable?

jem7sk

joelsfood wrote: »

Lots of thigns it could be (STP comes to mind), which can be hard to tell without actually logging in and confirming.

Just out of curiousity, any reason you don't get rid of the 8 port switch and just plug everything into the 3750? Though, for regular home use, a 3750 is rather loud and large, particularly if you're just using a single VLAN, no management, etc.

I am wanting to get rid of the 8 port. Just can't get the 24 port to work on the corporate LAN by plugging it into the wall port like I did with the 8 port.

jem7sk

Hondabuff wrote: »

Do in order on the 3750 first and report back.

Switch>enSwitch#erase startup-config
Erasing the nvram filesystem will remove all configuration files! Continue? [confirm]
[OK]
Erase of nvram: complete
%SYS-7-NV_BLOCK_INIT: Initialized the geometry of nvram
Switch#delete vlan.dat
Delete filename [vlan.dat]?
Delete flash:/vlan.dat? [confirm]
Switch#erase startup-config
Erasing the nvram filesystem will remove all configuration files! Continue? [confirm]r
Switch#
Switch#reload
Proceed with reload? [confirm]

I did this yesterday thinking I would be able to just plug in the switch afterward to the LAN and it would pass traffic as the unmanaged 8 port switch did.

jem7sk

Priston wrote: »

Is it a gig switch? Did you use a crossover or straight-through cable?

It is not a 10/100 switch and I am using a regular CAT 6 cable.. no crossover. Thanks all!

Am I wrong to think with the default factory setup it would work and pass traffic like the cheap unmanaged switch did without any special configuration?

AwesomeGarrett

Yes. If the engineer did their job, your switch won't just work. Disable spanning-tree, make all the interfaces static access ports or turn off auto negotiation, and it should work like a 'dumb' switch. This is assuming there's no limit on learned MAC addresses on the interface.

From what your describing with the lights, it sounds like it may be trying to negotiate a trunk and having a native VLAN mismatch. Network side=VLAN X and your side VLAN 1.

What you should do is contact whomever manages the network and have them add the switch to the network and configure it for remote management.

EDIT: It only take a few seconds of looped broadcast traffic to spike CPUs and before you know it the network is down.

Magmadragoon

Sounds like you were going to give the network engineer a rogue switch problem that would cause spanning tree problems if they did not use BPDUguard.

jem7sk

So I guess this will not work with the default factory configuration unless I do some configuring on my end.

joelsfood

I wouldn't try using it at all without some help/approval from networking. I'd missed in your first post. Depending on where you work, I've seen that as an infraction (hooking up unauthorized network equpiment) that can end up with you talking to HR.

mjsinhsv

It's called a "Resume Generating Oportunity".