BGW320 can't change LAN subnet?

If you change your Gateway's subnet, then any device already connected with a DHCP lease will lose connection until its lease times out and it renews it and gets a new IP on the new subnet.

Yup, I released the old lease and reconnected with a new lease and a new IP on the new subnet. So I'm able to reload the web UI on the router after changing the subnet, but any further actions---e.g. changing the wifi SSID, changing firewall rules, etc.---all that requires the access code and no longer works.

All those will require the System Access code... just like any other change you would make, either before or after you changed the subnet.

Thanks, @JefferMC , but maybe what I wrote wasn't clear.

I want to do a few different things here:

1. Change my LAN subnet from 192.168.1.255 to 192.168.99.255. (This will of course also change the router's own LAN IP address.)
2. Change my SSID and WPA passphrase.
3. Change some firewall rules.

I realize, as you said, that I need the access code to do all of those, including items 2 and 3. That's a perfectly reasonable security requirement.

My problem is that if I do #1 (change the LAN subnet, then reconnect my LAN clients, then go to the router's config page on its new IP address), then the access code doesn't work any more. If I then try to enter the access code to do items 2 and 3 the router tells me that I have the wrong access code. I've tried this multiple times, copy/pasted it to avoid mistakes, entered it carefully by hand in case it didn't like copy/pasting, etc. etc. It just doesn't accept the access code once the LAN subnet is changed from 192.168.1.255 to 192.168.whatever-else.

After changing the LAN subnet I'm able to reconnect my clients to the router. I'm able to get online. I'm even able to browse to the router's web-config page on its new LAN IP address. All that works just fine. But I can no longer enter the access code to do anything else.

I've never heard of anyone having an issue with the System Access password changing just because you changed the IP subnet.  Mine did not, and I changed my subnet a long time ago.  Have you tried changing your System Access password to a different value, confirming that the change took, and THEN changed the local IP range?

I also assume that you've done at least one Factory Reset (probably more than one, to get the default System Access password back).

I've never heard of anyone having an issue with the System Access password changing just because you changed the IP subnet

Hah yeah it seemed bizarre to me too, that's why I checked it multiple times before posting here.

Have you tried changing your System Access password to a different value, confirming that the change took, and THEN changed the local IP range?

Just tried that twice and that didn't work either. I can change pretty much anything and it's fine---except the LAN subnet, at which point it stops accepting the access code for anything.

I also assume that you've done at least one Factory Reset

Just to confirm that we're on the same page: you're talking about pushing the little red reset button on the back, correct? Yes, I've done that multiple times after it's refused to accept my access code. That's the only way for me to get back to a working access code.

I'm on firmware version 4.21.1. Is that what you have too?

4.21.1?  I don't know the last time I saw a .1 of anything.  Normally by the time it gets out here it's .4 or .5.  I'm running 4.22.5 and have been since April.  I've heard that some people have 4.23.4.

You should have gotten a firmware upgrade off 4.21.x by now.  I'm thinking you should probably call in for a replacement BGW.

Thanks @JefferMC that's very helpful! I'll message them today.

Update on this for anyone else having this issue: I requested a new router, they sent me a BGW320-500 (my original router was a -505), and...it turned out to have a different set of issues. When I tried to set it up the app was able to detect the new router (so I'd connected it correctly) but it still remained stuck on "Verifying account...", and I wasn't able to set up the router successfully. I eventually sent it back and decided to live with the problem with the 505.

But then I tried one more thing: when I set a new access code the router told me the code had to be between 8 and 32 characters long, so I'd been using a 32-char code. I decided to trim it to 12 characters (same length as the one printed on the router) and to do it from a different browser (which I thought I'd tried before but I can't remember now). The combination of 12-char password and new browser worked: I'm now able to change the LAN subnet and also the access code.

Also, the 505 router remained on firmware 4.21.1 for a few weeks and then a couple of days ago it updated to 4.23.4. (Btw, the replacement -500 they sent me was on 3.something.)

Thanks again for wrestling with this with me @JefferMC .