I tried to set up a bridge to extend my wifi connection following the instructions here.
Some background: I've followed this setup before and it worked. I also added a bind9 server to host my own DNS. Both were working well until recently when my raspberry pi randomly shut down. I restarted it with no internet access. I also stopped using it as a DNS because I couldn't be bothered to fix it at the time.
Today I started my once fully connected raspberry pi to find that it could not access the internet; it was trying to resolve DNS through 127.0.0.1. Thinking that this was a bind9 issue, I uninstalled bind9 and purged it, but to no avail; now there was just no DNS server. I tried again by undoing the steps in the access point bridge and uninstalled hostapd and I regained internet access. Going through and re-doing those changes caused me to lose my internet connection once again.
Since I can't ssh into my raspberry device, it's hard to copy paste files, so I'll type the non-comments from these files:
denyinterfaces wlan0 eth0 hostname clientid persistent option rapid_commit option domain_name_servers, domain_name, domain_search, host_name option classless_static_routes poption interface_mtu require dhcp_server_identifier slaac private interface eth0 interface br0