Initial Setup of a MikroTik CRS309 Switch

root

April 5, 2025

Setting up a new MikroTik CRS309 turned out to be a bit more complicated than anticipated.

This post outlines my process of setting up the switch. The screenshots show the newer gui as I’m reconstructing this process after setting everything up.

The MikroTik manual states you need to use a windows program called winbox but I found out, the switch has a web gui running on port 80, so thats what I used. The switch boots up with an ip of 192.168.88.1 and a netmask of 255.255.255.0 so you need to set some ip in the same subnet to access the web gui.

On Linux, run this as root ip address add 192.168.88.8/24 dev <interface> and then open the admin gui at http://192.168.88.1.

The manual [1] says sometimes you only need the username admin and no password and sometimes the password is printed on the sticker of the switch - in my case, it was the latter.

Change RouterOS Password

After logging into RouterOS, the first thing to do, is to change the password.

change password

Setup Networking

The next step is to configure a few network related things. In my case, I changed it over to dhcp so becomes its part of my 10.x.x.x network and i can access it without any static ip hackery.

initial settings

The dhcp became active immediately after saving. You can now log in using the ip you’ve configured on your dhcp server.

Change SWOS Password

According to Jeff Geerling [2] the next step is to also change the password for the SWOS admin user. In the console, type /system swos password.

change swos password

Update RouterOS

Next, update RouterOS under System > Package

update router os

Update Firmware

Using System > RouterBOARD > Upgrade one can upgrade the Firmware. Not quite sure what this is, but its up to date now.

update firmware

Switch to SwitchOS

This wasn’t so straight forward, and just changing to SWOS in the GUI under System > RouterBOARD > Settings didn’t work. I got an error message refering to device mode and changing this setting just wouldn’t work.

The MikroTik Documentation for Dual Boot [3] states, that one needs to execute /system routerboard settings set boot-os=swos in the console, which then prints a weird message prompting to power cycle the switch, to confirm the change. After doing that, you’re free to change back and forth between RouterOS and SWOS in the GUI as much as you want, it seems.

Reboot the switch using System > Reboot

change to SWOS

SWOS Unresponsive?

After booting SWOS I wasn’t able to access the Switch anymore. It seems that, when you switch over to SWOS, the Switch suddenly gives itself a new mac address, which also means it’ll get a different ip in my network. After figuring that out (following the dhcps traffic using dhcpdump -i eth0 on the dhcp server helps), i was able to access the SWOS admin gui.

Update SWOS

In the Upgrade Tab, click Download & Upgrade if there’s an upgrade available

Done

I think that’s it - finally, we’re able to use this for what we bought it for: switching!

Epilogue

Resetting the Switch

I reset the Switch multiple times in writing this post and there’s multiple ways [4]. Neither of these ‘reset’ the installed packages or firmware, so I’m not sure how one would deal with broken packages after a bad update.