这段描述看的不是很懂，直连192.168.1.20配置的时候会出现反复重启的情况，搞没搞清它的DHCP进程是如何工作的。所以后来就老实点在AP和AC之间接个交换机，当然这中间还是有个可DHCP的路由连在交换机上。有几次实在偷懒，直接将AP通过网线连在AC似乎两头都是在586b，但是在windows AC上启动了tftpd32 这个DHCP分发软件再也没遇到AP反复重启的情况。
http://wiki.ubnt.com/UniFi_FAQ#AP_status_stucks_at_.22adopting.22._What_do_I_do.3F
AP status stucks at adopting . What do I do?make sure AP has access to Internet (e.g. SSH into the AP and ping unifi, it should come back right away, even if it fails)install 2.2.5 or aftergo through the wizard and use ubnt/ubnt as admin’s username/passwordconnect UniFi APs and laptop (with controller installed) to the same routercheck the router and write down the IPs of the APs. Most home routers have it listed under DHCP client tableSSH into each problematic AP and issue ‘syswrapper.sh restore-default’
If above doesn’t help and your AP always show IP as 192.168.1.20. Check your DHCP server or router, if it did assign an IP to the AP yet the AP still shows 192.168.1.20, you may have a faulty AP. If all attempt fails, try the following:from the UI, make sure AP does obtain the IP from DHCP, note the IPfrom Controller PC, SSH into the AP (using the IP, default username/password is ubnt/ubnt)tail -f /var/log/messagescopy the text along with your support info (Admin- Support Info) to support@ubnt.com
The adoption process was designed with DHCP in mind. We do not encourage adoption through the default IP. However, if you are more used to that way, there is one rule: we do NOT recommend (at all) directly connecting your controller to the AP through a power adapter. Always put aswitch in between your controller and the target AP. The reason is that the adoption process involves AP rebooting, therefore if you directly connect AP to the controller Ethernet, this link will become up-and-down during the adoption process. In that case, there is a remote chance that the controller may not populate the correct inform IP address to the AP which will cause adoption stuck. In short, don’t adopt this way: directly connecting your controller to the AP through a power adapter .