Install and Setup Tailscale on Ubuntu

Add the Tailscale package

curl -fsSL https://pkgs.tailscale.com/stable/ubuntu/lunar.noarmor.gpg | sudo tee /usr/share/keyrings/tailscale-archive-keyring.gpg >/dev/null
curl -fsSL https://pkgs.tailscale.com/stable/ubuntu/lunar.tailscale-keyring.list | sudo tee /etc/apt/sources.list.d/tailscale.list

Update and install Tailscale

sudo apt update && sudo apt upgrade
sudo apt install tailscale
sudo tailscale up

You’ll be given a link to visit to authenticate the device.

You can check the Tailscale IP address with

tailscale ip -4

https://tailscale.com/kb/1275/install-ubuntu-2304

How to Install Mikrotik RouterOS on VirtualBox


Note that there are a couple of limitations of using the Cloud Hosted Router (CHR). The main issue is that the default license doesn’t allow for more than 1Mbps on each interface.

https://help.mikrotik.com/docs/display/ROS/Cloud+Hosted+Router%2C+CHR#CloudHostedRouter,CHR-CHRLicensing

Download the VDI version of CHR from the Mikrotik downloads page.

https://mikrotik.com/download

Mikrotik has instructions for installing CHR in VirtualBox, so this post is more of just a summary.

https://wiki.mikrotik.com/wiki/Manual:CHR_VirtualBox_installation

  1. Create a VM with Type Linux, Version Other Linux (64-bit)
  2. While setting up the VM, select the VDI downloaded from Mikrotik as the virtual disk.
  3. Start the VM and login with admin for the username and nothing for the password.

The easiest way to spin up more vm’s to right click on the VM and Clone.

Configure SNMPv3 on Cisco Router

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/snmp/configuration/xe-16/snmp-xe-16-book/nm-snmp-cfg-snmp-support.html

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

Setup Remote Syslog on Cisco

Configure Logging

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.

https://community.cisco.com/t5/networking-knowledge-base/how-to-configure-logging-in-cisco-ios/ta-p/3132434

Set timezone

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

Here are just the commands

terminal config
logging on
logging logserveraddress
clock timezone UTC 0
quit
wr

Cisco, Reload in X Minutes and Canceling

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:

  1. Run the command “reload 10” to reboot the router in 10 minutes. The plan is to cancel the reload after making sure our changes work
  2. Make the needed changes to the Router.
  3. After verifying that everything is working, run the “reload cancel” command to cancel the reload
  4. Now we can run “write” to save our new config

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

Simple OSPF between Mikrotik Routers

https://help.mikrotik.com/docs/display/ROS/OSPF

Setting up OSPF between Mikrotik routers is not too difficult. The following commands should work with RouterOS version 7+. Run these commands on each Mikrotik changing out the router-id.

Create a Loop-back interface

First it would be a good idea to create an loopback interface that will stay up. We’ll use this address as the router-id. This should be unique per router.

/interface/bridge/add name=loopback
/ip/address/add address=1.2.3.4 interface=loopback

Now lets setup OSPF.

Create OSPF Instance

First we’ll create the instance. Use the address from the above loopback address. Technically you can use whatever id you want as long as it is a 32 bit “address” and is unique.

/routing/ospf/instance/add name=default router-id=1.2.3.4

IMPORTANT NOTE: If this router is also the default gateway, you’ll need to specify the “originate-default=always” option to share the default gateway over OSPF to the other routers. You don’t have to do this if you don’t want to share the default route.

Create OSPF Area

Now we can create an OSPF area. For a simple OSPF setup, we’ll just use the default 0.0.0.0 area.

routing/ospf/area/ add name=default area-id=0.0.0.0 instance=default

Create Instance

Now we can add an instance. This is responsible for what networks get shared with OSPF. If you want to do all the addresses on the router, then use 0.0.0.0/0. If you only want to do specific networks, run an entry for every network, changing 0.0.0.0/0 to the network of interest.

/routing/ospf/interface-template/add networks=0.0.0.0/0 area=default

Wrapping Up

After that we can check to make sure things worked.

/routing/ospf/neighbor/print

You should see at a neighbor. It can take a little bit for the neighbors to show up.

You can also check the routes on the router.

/ip/route/print

OSPF has a default distance of 110, so checking the routes is a quick way to verify the routes are getting updated. Do note that if you have a static route in with a lower distance, that will take precedence over OSPF.

What is Cisco VTY?

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

List of Default IPv4, IPv6, and MAC Multicast Addresses

Here is a list of common Multicast addresses.

Mac Addresses

LLDP01:80:C2:00:00:0E
CDP (Sends messages to)01:00:0C:CC:CC:CCMore info
MAC address Multicast Addresses

IPv4

OSPF – Neighbor Discovery (All Routers)224.0.0.5
OSPF – DR/BDR224.0.0.6More info
IPv4 Multicast Addresses

IPv6

All IPv6 DevicesFF02::1
All IPv6 RoutersFF02::2
OSPFFF02::5
EIGRPFF02::A
Router Solicitation?FF01::1?
IPv4 Multicast Addresses