I have an SR520 that has been working. There have been no changes other than disconnecting the WAN connection for the weekend and plugging it back in. Now it absolutely will not renew the dhcp address on the wan. I am connecting it to a static router from ATT with a dhcp pool with public addresses. I connected my PC to the same cable and got an address right away.
I have had this problem with other SR520 routers that dont want to immediately accept/renew/recieve the dhcp address on the WAN port (FE4).
Is there a renew/release function for this port? How do I troubleshoot it?
One more thing . . . . check this config file. Last summer, a few initial SR520's shipped with a config that had a DHCP bug. This config was updated in manufacturing, and all subsequent units shipped with this config which fixed the DHCP issue.
If your DHCP problem is the same one then this config could fix it.