Lesson learned: Check router's DHCP allocation limit when you get 'Cannot connect to internet due to self-assigned IP address' error

Tadashi Shigeoka ·  Thu, May 26, 2016

The title says it all, but here’s a story about actual network troubleshooting I did today.

Recently, due to switching router equipment, when trying to connect PCs and mobile devices in our logistics warehouse to Wi-Fi, the error “Cannot connect to internet due to self-assigned IP address” started occurring frequently.

The conclusion was that the DHCP allocation limit of the switched router, Aterm WG1800HP2, was only 32 devices, which was quite low for Wi-Fi devices.

The IP address range that Aterm WG1800HP2 assigns via DHCP is detailed in the following article:

This router can automatically assign IP addresses (DHCP) to up to 32 devices. Beyond that, by assigning fixed IP addresses to individual devices, it can connect up to 32 + 221 = maximum 253 devices.

Originally, the router PR-500KI that we were renting from NTT was higher performance, so we didn’t encounter this DHCP allocation limit issue.

Reference Information

That’s all from the Gemba.