Broken DHCP on the Ubiquiti EdgeRouter Lite

The Ubiquiti EdgeRouter Lite (ERL), an amazing little networking box.

Back in October I finally squeezed gigabit speeds out of my AT&T Fiber connection by switching from my old OpenWRT-based TP-Link Archer C7 routers to an Ubiquiti EdgeRouter Lite (ERL). The Archer hardware could not keep up with gigabit speeds but the ERL can.

I love the ERL! It’s only about $100 but it’s a very powerful device! Previous versions of the firmware were a bit cryptic (at least in the UI area) but the latest one provides a lot of functionality (and wizards).

I had followed one such wizard to do my initial setup with the ERL back in October, after upgrading it from version 1.9.1 of EdgeOS to EdgeOSv1.9.7+hotfix.4. All seemed to work … except for it properly pulling a DHCP address from AT&T. See, I have bypassed AT&T’s PACE router in favor of my own and the ERL now does everything but the initial 802.1x authentication that opens the port on AT&T’s switch.

Why do you need to use DHCP on your AT&T link? You can put a static IP on your end of the link but AT&T offers DHCP leases of 14 days and expects you to use them. If your box (i.e., my ERL) doesn’t renew its IP near the end of those 14 days, AT&T considers the link to be dead and shuts down the connection. At this point, the only way you’ll get it going again is to reconnect the AT&T router and let it do its 802.1x authentication again. This is a pain, so avoiding it is very useful.
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