# How To Find IP of 3COM switch ???



## silversleeper (Oct 8, 2004)

So, I've managed to setup a managed switch with multiple VLANs to serve for a little project of mine. Now, I am having trouble getting my switch to communicate with the LAN. Here is a basic outline of my setup:

Cisco 3560G ---> 3COM SuperStack switch ---> WinServer2003 w/ISA Server 2006 ---> Internet

My VLANs on the Cisco switch are communicating with each other just fine, but cannot access the LAN that exists on the 3COM switch, and cannot access the internet beyond the 3COM switch.

I'm suspecting the 3COM switch is just running out the box, unconfigured. I've acquired this network from the previous IT folks, who didn't actually set any of it up, but have a consultant come in and configure it all. And for those that wish to know, this is in an office environment, a small one albeit. There currently isn't any mission critical work being performed. But I would like to be able to fix my problem without taking anything down.

I believe since the switch isn't configured (just an assumption) the port that my Cisco switch connects to the 3COM with is not configured with 802.1q encapsulation or trunking. 

I need to obtain access to the web management of the switch in order to enable this. My question to you folks is, how do I go about finding the IP address of this particular switch? As far as I know, it may have one assigned to it via DHCP from the DHCP server that resides on it.

The DHCP server is a Win Server 2003 box.
The switch is a 3COM 3300 SuperStack II 24 port switch

And if there's anything else you need from me, just holler. I'm looking into sourcing a serial F/F cable so I can attempt to console into the switch, hoping that the default passwords will suffice. I just wanted to avoid the console portion since that would involve learning the language to a certain extent. I just spent quite a bit of time learning how to program the Cisco switch all on my own and managed to do so successfully according to the Cisco TAC. In any event, your help in this matter would be greatly appreciated. 

Thanks!


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## silversleeper (Oct 8, 2004)

Quick update. I managed to find myself a serial cable and consoled into the switch and located the IP addy via ip interface display command. turns out the CLI isn't all that difficult to understand. Now hopefully I can get the VLANs forwarding through this switch properly.


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## 2xg (Aug 5, 2009)

Good to hear that, in the near future that you need locate an IP address within your IP subnets, you may use Advanced IP Scanner.


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## silversleeper (Oct 8, 2004)

Thanks for the tip 2xg. It turns out that the IP was configured on the main switch in the stack, using a totally different subnet, which explains why the 3COM Network Supervisor software was not able to find it before until I specified that subnet. 

I managed to get into the switches web interface and changed the port setting for the port going to my Cisco switch. The setting that I changed was the FWD UNKNOWN VLAN TAGS setting seen below:









This however has not enabled me to ping from the Cisco switch to the 3COM switch or any devices on the 3COM LAN. I have enabled dot 1q trunk encapsulation on the Cisco end and put the port in trunk mode. What am I missing on the 3COM end?


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## 2xg (Aug 5, 2009)

Make sure that your 3Com switch is not set to auto negotiation as well. Manually configured the ports for 100-Full on both Cisco and 3Com Switches then do a test see if they communicate.


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## silversleeper (Oct 8, 2004)

i set it on the 3COM switch to 100FD. I attempted to set the Cisco end to 100FD but it turned the port off. The port turned on again after resetting it to AUTO.


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## 2xg (Aug 5, 2009)

Are you using a crossover cable between the 2 Switches? Have you tried changing the cable?


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## silversleeper (Oct 8, 2004)

Hmm... I have overlooked this minute factor. I will check and post an update tomorrow. Heading out for the day. Thanks so much for your assistance thus far!


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## silversleeper (Oct 8, 2004)

Alright, went out and purchased a new crossover cable for safe measure and ran it from my Cisco switch to the network drop going into the 3Com switch. I'm still unable to ping the 3Com or the LAN/Internet from the Cisco switch.


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## 2xg (Aug 5, 2009)

This is a bit suspicious. Someone else setup the network and it wasn't you. Do you have to have it on a 'Managed Switch' for both switches and not 'Unmanaged' ?


> I'm suspecting the 3COM switch is just running out the box, unconfigured. I've acquired this network from the previous IT folks, who didn't actually set any of it up, but have a consultant come in and configure it all. And for those that wish to know, this is in an office environment, a small one albeit. There currently isn't any mission critical work being performed. But I would like to be able to fix my problem without taking anything down.


or....unless you want to do a reset of the 3Com Switch do factory defaults?


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## silversleeper (Oct 8, 2004)

I'm not sure what your question means exactly. They are both "managed" switches. Here are the specs:

Cisco WS-C3560G-48TS-S [48 port gigabit L3 switch]
3Com SuperStack II 3300 [3 switches in stack configuration]

I'm unsure if the factory reset of the 3Com will undo the stack configuration. If so, I would have to research how to re-configure it before venturing down that path.


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## 2xg (Aug 5, 2009)

I think you better stick with Managed Switches bec. of the VLAN's. As for your 3COM Switch, I don't know what else to suggest you, but a reset to factory default. There's something misconfigured there by the previous IT people. Of course do a research first on how to reconfigure the Switch.


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## silversleeper (Oct 8, 2004)

Okay, heres a little something that may be helpful to you in helping me diagnose this. 

I am using a machine that sits on the 3Com switch, connected via ethernet. The IP assigned via DHCP via Server2003 is 192.168.0.x. The 3Com switch IP is 209.120.x.x. I cannot access the web interface of the switch without manually assigning my PC a same subnet IP as the 3Com switch.

I am however, able to connect to the Cisco switch using the same PC sitting on the 3Com switch. However, this can only be done by manually assigning my PC a same subnet IP as the Cisco switch IP, which happens to be 10.0.x.x. Once I am in the same subnet, I am able to telnet into the switch over ethernet, or connect use Cisco Network Assistant.

From within the Telnet session with Cisco switch, I can ping my VLANs. From PC, I am not able to ping Cisco VLANs. 

Not sure if that makes things clearer or fuzzier for you.


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