How to configure SNMP v3 on Cisco Switch, Router, ASA, Nexus (bestmonitoringtools.com)
Enter configuration mode
enable conf t
Everything in bold you should look at changing.
snmp-server view ViewDefault iso include snmp-server group GroupName v3 priv read ViewDefault snmp-server location address snmp-server user MyUsername GroupName v3 auth sha AuthPass1 priv aes 128 PrivPass
Exit and save changes
exit write
Now we can verify the snmp details with
show snmp
First we need to drop into configuration mode
conf t
Now we run the following command. Change ip-address to the address of you remote syslog server.
logging host ip-address
You will want to make sure that your time/timezone is correct.
Change UTC and 0 to your your timezone and how many hours off UTC you are. For example for EST you would do EST -5
clock timezone UTC 0
Add OSPF on a port
Change 1 for the OSPF instance ID.
interface ge/1/1
ip ospf 1 area 0
Set default-information originate
Default-information originate is used to share the default route with other routers.
In the following command change 1 to your OSPF instance ID
router ospf 1
default-information originate always
Cisco’s can be rebooted with the reload command. The reload command allows you to specify how many minutes like
reload 5
to reload in 5 minutes. We can also reload at a specific time. For instance
reload 13:30
will reload the router at 1:30PM.
For a Cisco config to remain permanent, we have to “write” i.e. save the config. By default, making changes, for instance an IP address on an interface, will get wiped on a reboot or reload.
We can take advantage of this behavior to “test” changes on a Cisco router.
Example:
To recap reload 10 will reload a router in 10 minutes
If we loose access to the router while making changes, once 10 minutes has expired, the router will reload, returning it to the last know working state.
The reload cancel command will cancel the reload.write will make our config persistent across reboots/reloads
https://superuser.com/questions/1080513/cisco-router-auto-restart-in-x-seconds
Fast BSS Transition is a method for a device to seamlessly move move between Basic Service Set (BSS) AKA a Wireless AP’s, inside of an Extended Service Set (ESS) AKA, WLAN deployment.
This can help prevent Voip calls from dropping while someone is walking across campus or between buildings.
FT PSK is a Password option for Cisco equipment The idea is
Some more resources for learning more.
https://evanmccann.net/blog/2021/11/unifi-advanced-wi-fi-settings
https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/80211r-ft/b-80211r-dg.html
vty stands for Virtual Teletype. What is Teletype?
The teletype, or teleprinter, is a device used for communicating text over telegraph lines, public switched telephone network, Telex, radio, or satellite links.
Wikipedia explanation of teletype
https://en.wikipedia.org/wiki/Teleprinter
This means vty is essentially like a virtual computer screen plugged into the router that we can remotely access.
Both SSH and Telnet use this virtual monitor to let you see the router/switch.
The command
line vty 0 4
Configures 5 of these virtual teletypes (vty’s) for us to use. Can think of it having 5 monitors connected to the router. When you SSH to it, you are claiming one of these monitors. Cisco devices support up to a maximum of 16. 0-15
The following is some basic info on STP and RSTP. This list is not comprehensive. Refer to the link at the bottom of the page for more in depth details.
Default Priority is 32768 + VLAN ID
For example, if we are using vlan 10, then our default priority is 32768 + 10 = 32778
RSTP Priority can be set from 0 – 61440 in increments of 4096.
Ports can fill 1 of 4 roles.
| Port Role | Description |
| Root Port | Port closest to the Root Bridge (Switches going to the Root switch) |
| Designated Port | Ports going away from the Root Bridge (To clients) |
| Alternate Port | A “backup” port for the Root port. If the Root Port fails, this port takes over |
| Backup Port | Essentially a backup port for the designated port |
A port can be in one of 3 states. Well technically 4 states if you include down/unplugged.
| Port State | Description |
| Discarding | Port discards packets (Alternate and Backup Ports) |
| Learning | Port learns MACs and doesn’t forward data |
| Forwarding | Port forwards data and learns MACs |
There are 3 port Types. Not to be confused with port States or Roles.
| Port Type | Description |
| Point to Point | Switch to Switch |
| Point to Point Edge | Edge of Network. Connected to a PC, Printer etc. |
| Shared | Half Duplex, Port connected to a Hub |
There are three RSTP timers. STP has the same timers, but the MaxAge is 10 seconds, and the Forward Delay is used for both Learning and Listening states which takes a total of 30 seconds to complete.
| Timer Name | Default Value | Description |
| Hello Timer | 2 Seconds | Time between Hellos created by Root |
| MaxAge | 6 Seconds (Hello Timer * 3) | How long a Switch should wait before trying to readjust the network |
| Forward Delay | 15 Seconds | Delay used for Learning/Listening in STP. Shouldn’t be necessary if legacy bridges are not used. |
There are technically two types of cost. The newer cost values were introduced so we could use faster ethernet speeds.
By default Cisco switches use the old cost values, but they can be changed to use the new ones.
spanning-tree pathcost method long
| Ethernet Speed | Old Cost | New Cost |
| 10 Mbps | 100 | 2,000,000 |
| 100 Mbps | 19 | 200,000 |
| 1 Gbps | 4 | 20,000 |
| 10 Gbps | 2 | 2000 |
| 100 Gbps | N/A | 200 |
| 1 Tbps | N/A | 20 |
More information can be found at the following link.
https://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/24062-146.html
You can show the uptime on a Cisco router by running the following command.
show version
It will report a bunch of information about the router. look for the line that shows the uptime.
Swap out logserveraddress with the ip or hostname of your remote log server
terminal config
logging on
logging logserveraddress
quit
wr