cisco_interfaces_in_use
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| cisco_interfaces_in_use [2024/01/12 20:18] – walkeradmin | cisco_interfaces_in_use [2024/01/12 20:37] (current) – [Show the Mac Address Table] walkeradmin | ||
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| ==== Introduction ==== | ==== Introduction ==== | ||
| - | A really useful task to perform when looking at remote systems is to see what interfaces on a Cisco Switch are in use (as in connected). | + | A really useful task to perform when looking at remote systems is to see what interfaces on a Cisco Switch are in use (as in connected). |
| \\ | \\ | ||
| + | ==== Interface Status ==== | ||
| + | Lets look at how to see what interfaces we are using: <color # | ||
| \\ | \\ | ||
| < | < | ||
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| Gi0/ | Gi0/ | ||
| </ | </ | ||
| - | In the above example | + | In the above example |
| + | \\ | ||
| + | < | ||
| + | Port Name | ||
| + | Gi0/1 connected | ||
| + | </ | ||
| + | \\ | ||
| + | The following is what each field means: | ||
| + | < | ||
| + | Port - This is the interface number on the switch | ||
| + | Name - This only shows if any names have been assigned, generally they are not. | ||
| + | Status - Connected. | ||
| + | VLAN - What VLAN the interfaces is currently in. | ||
| + | DUPLEX - a-full (automatic-full) | ||
| + | SPEED - a-1000 (auto 1000) | ||
| + | TYPE - 10/ | ||
| + | </ | ||
| + | \\ | ||
| + | \\ | ||
| + | ---- | ||
| + | ==== Show the Mac Address Table ==== | ||
| + | We can use the following to show what MAC Addresses are present on each interface. If you have an interface that is connected to another switch then you will see all MAC addresses from that switch interface. | ||
| + | \\ | ||
| + | < | ||
| + | sh mac address-table | ||
| + | |||
| + | Vlan Mac Address | ||
| + | ---- ----------- | ||
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| + | </ | ||
| + | \\ | ||
| + | I want to look at this specific interface: | ||
| + | < | ||
| + | Vlan Mac Address | ||
| + | 2 | ||
| + | </ | ||
| + | It can be seen that this is interface 5 on our Cisco, that is in VLAN2 and there is a device connected to it with the MAC Address <color # | ||
| + | \\ | ||
| + | \\ | ||
| + | I have logged in to the server that I know is connected to this interface (the servers eno3 is connected) and if I run the command (Linux): | ||
| + | \\ | ||
| + | < | ||
| + | ip a show eno3 | ||
| + | |||
| + | 5: eno3: < | ||
| + | link/ether a4: | ||
| + | altname enp61s0f2 | ||
| + | </ | ||
| + | We can see that the link/ether address is listed as: a4: | ||
| + | \\ | ||
| + | \\ | ||
| + | ==== Look for a specific MAC Address ==== | ||
| + | Because there could be many MAC addresses present on an interface when you use the command <color # | ||
| + | \\ | ||
| + | < | ||
| + | sh mac address-table | incl af | ||
| + | |||
| + | Now the only result we get back is this: | ||
| + | 2 a4bf.0169.b7af | ||
| + | </ | ||
| + | We may not know what MAC we are looking for, but if we do this is very useful. | ||
| + | \\ | ||
| + | \\ | ||
cisco_interfaces_in_use.1705090684.txt.gz · Last modified: 2024/01/12 20:18 by walkeradmin