Determining IP address of previously configured SG200-26P Smart Switch

[Vince Ready]

I own a Cisco SG200-26P switch that was installed and configured by an A/V technician when our home was built.  I do not know the static IP address that was assigned to the switch, so I've been unable to connect to the web management console to configure features on the switch (such as the PoE port settings).

The switch is directly connected to my router on the 192.168.1.XXX subnet.  I've tried the factory default IP of 192.168.1.254, which didn't work, and I can see that the power light is solid (not flashing).

I've looked in the DHCP client list on my router to see whether the SG200 switch is using a DHCP-assigned address, but I don't see it there (I looked for its device MAC address), so I'm fairly confident that it has been configured with a static IP address.

What is the best way to locate the switch on my network and login to the web management console?  Is there a network discovery tool that would help me identify it?

Thanks in advance for the help!

Vince

[Julio E. Moisa]

Hi

Try to execute on the command prompt of your computer:

arp -a

it could provide some info. 

[Vince Ready]

Thanks, Julio.  I appreciate the suggestion.  That hadn't occurred to me.  

Here's what I get:

Interface: 192.168.1.139 --- 0x5
Internet Address Physical Address Type
192.168.1.1 e0-2f-6d-75-70-d0 dynamic
192.168.1.100 00-18-dd-05-28-96 dynamic
192.168.1.101 00-1c-2a-f0-05-78 dynamic
192.168.1.103 b8-ac-6f-92-09-94 dynamic
192.168.1.104 00-08-9b-d5-6c-0c dynamic
192.168.1.109 0c-4d-e9-b3-b9-10 dynamic
192.168.1.120 00-21-5a-97-e0-7c dynamic
192.168.1.121 e8-c7-4f-04-90-5b dynamic
192.168.1.123 e8-c7-4f-04-90-08 dynamic
192.168.1.130 00-09-b0-45-29-71 dynamic
192.168.1.140 00-0e-58-27-4b-20 dynamic
192.168.1.141 b8-e9-37-97-ba-7e dynamic
192.168.1.143 00-0e-58-27-56-06 dynamic
192.168.1.144 74-75-48-f0-2e-0b dynamic
192.168.1.146 6c-c2-17-25-ea-4d dynamic
192.168.1.147 00-0e-58-45-50-08 dynamic
192.168.1.165 00-08-9b-f6-42-f9 dynamic
192.168.1.179 00-08-9b-f6-42-fa dynamic
192.168.1.201 88-dc-96-30-ce-ae dynamic
192.168.1.255 ff-ff-ff-ff-ff-ff static
224.0.0.22 01-00-5e-00-00-16 static
224.0.0.251 01-00-5e-00-00-fb static
224.0.0.252 01-00-5e-00-00-fc static
224.0.0.253 01-00-5e-00-00-fd static
239.255.250.250 01-00-5e-7f-fa-fa static
239.255.255.250 01-00-5e-7f-ff-fa static
255.255.255.255 ff-ff-ff-ff-ff-ff static

Unfortunately, I don't see the MAC address of the switch in this list.

[Julio E. Moisa]

is a Cisco router connected to switch? if it is, you could run show arp or show cdp command 

[Vince Ready]

Yes the router is a Cisco RV320.

Unfortunately, I'm not sure how to get to a command line or run arp on the RV320.

[Julio E. Moisa]

Are you able to reach the router via SSH or telnet? I have not worked with this router model but we can try to find a solution  :-)

[Vince Ready]

I have enabled SSH in the RV320 (under Firewall > General) but when I try to connect (tried from a command line as well as using PuTTY in Windows) I get access denied.

I don't know SSH well, so I could be doing something wrong.  I'm executing the following:

ssh admin@192.168.1.1

[Julio E. Moisa]

Click Firewall > General. Check Enable SSH to allow login from the LAN side.

http://www.cisco.com/c/dam/en/us/td/docs/routers/csbr/rv320/CLI_guide/rv32x_cli_guide.pdf

Try just ssh 192.168.1.1  from the command prompt.

[Vince Ready]

Just tried ssh 192.168.1.1 and tried to do an interactive login.

SSH is still enabled under Firewall > General

I'm still getting "Access Denied"

From what I've ready, the RV320 router doesn't offer a complete shell when you ssh to it, just a limited set of commands.

[Julio E. Moisa]

Also could you please check on the router, the IP address configured on the interface facing to the switch. That can provide us information that we need.

The switch could be working without IP address for management and every port configured on vlan 1. If the IP of the router is the same that you receiving on your computer, the theory could be true. The switch could be working with factory settings.  Do you have other network segments I mean other subnets provided by the router at your home?

[Vince Ready]

The LAN IP address on the router is set to 192.168.1.1/255.255.255.0

If the SG200 switch is working without  an IP address for management as you suggested above, how would you go about connecting to the web management interface?

[Julio E. Moisa]

You could reset the switch to factory setting:

http://mamchenkov.net/wordpress/2015/08/02/how-to-set-sg200-26p-to-factory-default-settings/

If there is a management IP , It should be on the same segment 192.168.1.0/24 , Also you could use an IP scanner to identify all the host on the subnet 192.168.1.0/24 over you network. 

[Vince Ready]

This did the trick.  I did a scan using the iOS app Fing, and I was able to locate it... turns out the switch is getting a DHCP address.  Just wasn't showing up in the client list in my router for some reason.

Thanks for all the help, Julio!   Have a great night!

[Julio E. Moisa]

Great! 

You are welcome, it was a pleasure assist you.

Please rate the comment if it was useful  :-) 

Thank you in advance.

Have a great night too!

[Vince Ready]

I have no other subnets in my network environment. 

It's pretty staight forward:

DSL modem in bridged mode allows RV320 router to use the public IP provided by my ISP.  Downstream, I have the Cisco SG200 switch with all of my wired Ethernet jacks terminating, as well as Ethernet connections from two wired access points.

The RV320 router provides DHCP for the entire network (DHCP pool is .100-.197) and several devices are configured with static IP addresses outside the DHCP range.