I bought a RB260GS running SwOS. I connected it to my ISP's fiber ONT, then my Mikrotik router to the switch. The switch is used for bypass purpose to isolate certain traffic based on L2 mac protocol between my ONT and my router.

After logging into SwOS's web GUI, I noticed that it detected latest SwOS update, suggesting that it has Internet access. This seemed bizarre to me because my ISP required specific cloned Mac address to grant a DHCP IP, and that is exactly what I configured my router to do, and it already got it. So how was SwOS able to connect to WAN? I cannot seem to find any info on what IP it got, what kind of DHCP client it's running and how to disable it etc.

Please enlighten me. Thanks!

I think the RB260GS has DHCP client mode automatically and reverts to fixed address if not acquired. One has to manually disable the auto DHCP feature.
Perhaps the RB260GS got assigned a dhcp?? Did you confirm it could actually get an upgrade??

I think the RB260GS has DHCP client mode automatically and reverts to fixed address if not acquired. One has to manually disable the auto DHCP feature.
Perhaps the RB260GS got assigned a dhcp?? Did you confirm it could actually get an upgrade??

Yeah the web upgrade works. I cant seem to find a way to even see what kind of IP it got.

How do you "manually disable the auto DHCP feature" on the RB260GS in swOS? I can't find that option anywhere on the web GUI.

Go to the SYSTEM page.
The first ENTRY is for ADDRESS AQUISITION.
The second ENTRY is for the STATIC ENTRY if the first entry does not acquire an IP.

Set the first entry to static to turn off the DHCP method.

Go to the SYSTEM page.
The first ENTRY is for ADDRESS AQUISITION.
The second ENTRY is for the STATIC ENTRY if the first entry does not acquire an IP.

Set the first entry to static to turn off the DHCP method.

Under my System page, there is no "address aquisition". The first field is the management/LAN IP of the switch (192.168.88.1), the second is the host name/identity (identity).
No trace of WAN IP/gateway/dns etc anywhere.

What version of SwOS are you running. I am using the latest 2.9 but I am pretty sure vers 2.8 had the same System page.
https://wiki.mikrotik.com/wiki/SwOS/CSS106#System

Hmmm, you may have older hardware variant of 260GS? If so look down to General Settings I think its there.

SwOS has no access to Internet - System page and update check is done client-side via JavaScript XHR request.