Technical: subnet mask limitation on new firmware?
Manually configured a new customer to co-exist with another Wi-Fi router used as an access point.
Subnet mask was 255.255.252.0 (/22) rather than the more typical 255.255.255.0 (/24).
DHCP issued IP on one Class C subnet, while router lived on adjacent Class C subnet.
Eg. IP: 192.168.128.1, subnet: 255.255.252.0 with default gateway: 192.168.129.1
Everything worked well for a week but this morning a bizarre problem occurred. Whether connecting via Wi-Fi or wired, DHCP did not work. All lights were normal, and behaviour was consistent after restarting all devices.
After full factory reset of the router, normal behaviour resumed. Attempted to restore previous settings but this time a new 'invalid subnet' error message occurred when setting network subnet to 255.255.252.0 (/22). This error did not occur previously.
Firmware is 7.1.1.2.7b8 (original firmware unknown).
Adding the restriction to a single Class C (/24) network would explain the behaviour. Everything appears to be normal, but can't reach the default gateway on an adjacent Class C subnet.
Q: Does anyone know whether the subnet has been recently restricted to a single Class C network?
For example, 255.255.255.0 is ok, but 255.255.0.0 is not.
Q: Does anyone know if the firmware just updated to 7.1.1.2.7b8.
I suspect, but can not confirm, a firmware update as the bufferbloat performance has improved.
Best Answer
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I have the same issue with that updated firmware. I get lots of disconnects or DHCP issues. There are lots of complaints about that problem yet FIZZ puts the blame on broken modems or that we have too much activities on them. Please stop lying to us and try to fix this issue ASAP please. Thank you 🙏
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Answers
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Hello, something is wrong with that firmware
I simply wanna change from this
To this
But after Saving Changes the modem IP is switched back to Default 🤪
So something is xxx up 🤔
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That was not my issue, and I can confirm that I was successfully able to change the IP.
I could not however change the subnet mask, that I could modify the day before.
If I remember correctly, there were some settings that did not update until I refreshed the screen.
But I don't think that this was one of them.
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With the IP or subnet issue, it will just stop working because it can't route properly.
A disconnect is likely an unrelated problem.
You sound more likely to have a marginal connection either internally (in your house) or externally (to the pole) or maybe your router itself.
If this occurs on Wi-Fi, my guess would be interference over which you have little control.
If this occurs when wired, change your network cable.
If that doesn't help, then blame the router or the pole.
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