occasionally i need to change the mac address in order to get another ip address and routes due to poor connections. however i found that openwrt cant get connected to my isp's dhcp unless i unplug the lan cable or power it off, note that restarting related services (and interfaces perhaps) or router does not work either. i have also tried to remove the dhcp lease thing but no luck. this should not be the isp or modem problem since once i removed the current lan cable conneted with my openwrt router and replaced it with, for instance, another lan cable connected to my pc it can get a new ip without problem
this seems a minor bug where i can get another ip after changing my mac address on linux and windows by restarting the interface only. i have tried on my old tp link router as well as my netgear, with openwrt 17 , 19 etc and probably one of the lede releases
Tear down the connection (ifdown wan) first, so the DHCP lease gets released, the ISP is probably fighting against multiple concurrent logins and catches you that way (the ISP might also insist on physically severing the connection or a timeout, before allowing a new connection).
The DHCP renew rule has no hits, so the problem appears to be on the DHCP server side.
It's best to contact the ISP and ask them if you are allowed to use a dynamic MAC.
Also let them verify that the DHCP server works correctly with your MAC.
there should be no problem with their server since they asked me to changed my mac address before to avoid poor connections. also as i said before, it only happen when openwrt/lede is involved, if i remember correctly, the old tp link router didnt have this problem with their firmware installed.
moreover, during the installation of my broadband we were testing the speed and switched between a few devices including my linux box, a laptop etc without problem. but when it was connected to my router with openwrt installed it just didnt work.
so can you get another ip successfully after changing the mac address with openwrt? i believe it's a bug regarding the dhcp client for not able to talk to the dhcp server, perhaps the old mac address is still in use or unable to release it but forced to connect with the new mac address. just my two cents