2/1/2022

How To Find Switch Ip Address From Pc

If you have a big network with multiple Access Switches connecting to the core switches or routers then tracing a device like a PC or a laptop for troubleshooting or security purposes is one of those tasks that you often end up doing. This is not a difficult task but can certainly be time consuming.

  1. How to Find the Fixed IP Address of a Device on a LAN. Most troubleshooting steps involve working with commands and other tools that require you to know your device's IP addresses. You need to find out the private IP address for your router and the IP addresses for any switches, access points, bridges, repeaters, and other hardware in the network.
  2. To find the IP Address via the command line, we need to first open the terminal. To do that, hit Cmd + Space to trigger Spotlight Search. Type “Terminal” on the search bar. Click on the Terminal icon when the search results populate.

It'll find.every. active IP address in the subnet for you - you then just have to try and connect to the ones you.don't. recognise - changes are one of them will be the switch. It is possible that the switch doesn't HAVE an Ip address - the 2950 is a layer two switch, and the only IP address on it would be for management - and unless someone.

Lets start with an IP address on hand. If you have an IP address on hand quickly ping and check if the device is pingable. If yes, then simply logon to one of your core switches or routers and do a simple sh ip arp

Core1# sh ip arp 192.168.1.15

Protocol Address Age (min) Hardware Addr Type Interface
Internet 192.168.1.15 22 0000.1111.1111 ARPA Vlan1

From the above you know the MAC Address of for the device:

IP Address : 192.168.1.15
MAC Address : 0000.1111.1111

Now, do a show mac-address command on the core switch or router. This will show the interface to which it is connected or through which it is learned.

Core1# sh mac-address-table address 0000.1111.1111

How To Find Switch Ip Address From Pc

Legend: * – primary entry
age – seconds since last seen
n/a – not available

vlan mac address type learn age ports
——+—————-+——–+—–+———-+————————–
Supervisor:
* 1 0000.1111.1111 dynamic Yes 10 Te1/1

This indicates that the device is either connected to the port or though another switch which is connected to the interface. Looking at this, it is very likely that this is a uplink (TenGigabit Ethernet link) to another Distribution or Access switch.

Sometimes, the output might show as follows [note the Po1]

Legend: * – primary entry
age – seconds since last seen
n/a – not available

vlan mac address type learn age ports
——+—————-+——–+—–+———-+————————–
Supervisor:
* 1 0000.1111.1111 dynamic Yes 10 Po1

This indicates that there is a etherchannelis being setup. So do a 'show etherchannel' command to find the phsycial ports that are paired.

Core1# show etherchannel summary
Flags: D – down P – bundled in port-channel
I – stand-alone s – suspended
H – Hot-standby (LACP only)
R – Layer3 S – Layer2
U – in use f – failed to allocate aggregator

M – not in use, minimum links not met
u – unsuitable for bundling
w – waiting to be aggregated
Number of channel-groups in use: 6
Number of aggregators: 6

Group Port-channel Protocol Ports
——+————-+———–+———————————————–
1 Po1(SU) – Te1/1(P) Te2/1(P)

This shows the ports Te1/1 or Te2/1 as a source through which the address is learnt.
Now, do a 'show cdp neighbors' to show the directly connected devices.

Core1# sh cdp neighbors

Capability Codes: R – Router, T – Trans Bridge, B – Source Route Bridge
S – Switch, H – Host, I – IGMP, r – Repeater, P – Phone

Device ID Local Intrfce Holdtme Capability Platform Port ID
Access1 Ten 1/1 129 R S I WS-C6509 Ten 1/1

That tells you, it is the Access switch 1 that is connected to Te1/1 and not the device itself.

Now, log onto the Access switch and do a 'show mac-adddress-table' command for the MAC address and that should show the interface to which it is connected

[NOTE: unless it is a distribution switch to again there are a bunch of Access switches connected in which case, you need to go through the whole procedure as above again]

Access1# show mac-address-table 0000.1111.1111

vlan mac address type learn age ports
——+—————-+——–+—–+———-+————————–
Supervisor:
* 1 0000.1111.1111 dynamic Yes 10 Gi1/24

As you can see which port the device is connected and on which switch.

Now do a 'show interface' command to show the port details.

How To Find Switch Ip Address From Pci

Access1>sh int gigabitEthernet 1/24

Set Ip Address On Switch

GigabitEthernet1/24 is up, line protocol is up (connected)
Hardware is C6k 1000Mb 802.3, address is xxxx.xxxx.xxxx (bia xxxx.xxxx.xxxx)
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s
…..

..
.

There you go you found the device switchport that you tried to trace!!!

How To Find Switch Ip Address From Pc Windows 10

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