I know Ubiquiti devices to be tricky with local hostnames unless dnsmasq is enabled on them, but that would normally exhibit a failing reverse dig as well. And yours seems to work.
I am out of ideas as to what's causing your issue. 
You may try setting up your router as Pi-hole's sole upstream - with Never forward reverse lookups for private IP ranges unchecked - instead of using Conditional Forwarding, but will then have to control final upstream DNS through your router's settings.
This should be sufficient to get hostname resolution on the dashboard.
Please add
DEBUG_API=true
to /etc/pihole/pihole-FTL.conf (create if it does not exist, you may need sudo-powers) and run
pihole restartdns
After a while, you should see lines like Trying to resolve XYZ in /var/log/pihole-FTL.log.
How do they look like exactly?
Here you go:
[2020-04-08 17:56:59.743 872] *****************************
[2020-04-08 17:56:59.743 872] * Debugging enabled *
[2020-04-08 17:56:59.743 872] * DEBUG_DATABASE NO *
[2020-04-08 17:56:59.743 872] * DEBUG_NETWORKING NO *
[2020-04-08 17:56:59.743 872] * DEBUG_LOCKS NO *
[2020-04-08 17:56:59.743 872] * DEBUG_QUERIES NO *
[2020-04-08 17:56:59.743 872] * DEBUG_FLAGS NO *
[2020-04-08 17:56:59.743 872] * DEBUG_SHMEM NO *
[2020-04-08 17:56:59.743 872] * DEBUG_GC NO *
[2020-04-08 17:56:59.743 872] * DEBUG_ARP NO *
[2020-04-08 17:56:59.743 872] * DEBUG_REGEX NO *
[2020-04-08 17:56:59.743 872] * DEBUG_API YES *
[2020-04-08 17:56:59.743 872] * DEBUG_OVERTIME NO *
[2020-04-08 17:56:59.743 872] * DEBUG_EXTBLOCKED NO *
[2020-04-08 17:56:59.743 872] * DEBUG_CAPS NO *
[2020-04-08 17:56:59.743 872] * DEBUG_DNSMASQ_LINES NO *
[2020-04-08 17:56:59.743 872] * DEBUG_VECTORS NO *
[2020-04-08 17:56:59.743 872] *****************************
[2020-04-08 17:56:59.831 872] INFO: No regex whitelist entries found
[2020-04-08 17:56:59.841 872] Compiled 0 whitelist and 5 blacklist regex filters in 29.5 msec
[2020-04-08 17:57:00.315 872] Trying to resolve 10.0.0.1
[2020-04-08 17:57:00.329 872] Trying to resolve 10.0.1.89
[2020-04-08 17:57:00.342 872] Trying to resolve 10.0.0.116
[2020-04-08 17:57:00.355 872] Trying to resolve 10.0.1.5
[2020-04-08 17:57:00.368 872] Trying to resolve 10.0.1.64
[2020-04-08 17:57:00.380 872] Trying to resolve 10.0.1.65
[2020-04-08 17:57:00.393 872] Trying to resolve ::1
[2020-04-08 17:57:00.393 872] 7 / 7 client host names resolved
[2020-04-08 17:57:00.393 872] Trying to resolve 10.0.0.254
[2020-04-08 17:57:00.406 872] 1 / 1 upstream server host names resolved
[2020-04-08 17:58:01.320 872] Trying to resolve 10.0.1.44
[2020-04-08 17:58:01.426 872] Trying to resolve 10.0.1.19
[2020-04-08 17:58:01.438 872] 2 / 9 client host names resolved
[2020-04-08 17:58:01.439 872] 0 / 1 upstream server host names resolved
[2020-04-08 17:58:16.672 872] New upstream server: 127.0.0.1 (1/1024)
----------------------------------------------------------------------------------------------------------------2020/04/08 17:58:59----------------------------------------------------------------------------------------------------------------
[2020-04-08 17:59:00.000 872] Trying to resolve 10.0.1.67
[2020-04-08 17:59:00.121 872] 1 / 10 client host names resolved
[2020-04-08 17:59:00.121 872] Trying to resolve 127.0.0.1
[2020-04-08 17:59:00.121 872] 1 / 2 upstream server host names resolved
[2020-04-08 18:00:00.198 872] 0 / 10 client host names resolved
[2020-04-08 18:00:00.198 872] 0 / 2 upstream server host names resolved
[2020-04-08 18:00:00.703 872] Trying to resolve 10.0.0.1
[2020-04-08 18:00:00.717 872] Trying to resolve 10.0.1.89
[2020-04-08 18:00:00.731 872] Trying to resolve 10.0.0.116
[2020-04-08 18:00:00.744 872] Trying to resolve 10.0.1.5
[2020-04-08 18:00:00.758 872] Trying to resolve 10.0.1.64
[2020-04-08 18:00:00.771 872] Trying to resolve 10.0.1.65
[2020-04-08 18:00:00.785 872] Trying to resolve ::1
[2020-04-08 18:00:00.785 872] Trying to resolve 10.0.1.44
[2020-04-08 18:00:00.799 872] Trying to resolve 10.0.1.19
[2020-04-08 18:00:00.817 872] Trying to resolve 10.0.1.67
[2020-04-08 18:00:00.830 872] 10 / 10 client host names resolved
[2020-04-08 18:00:00.830 872] Trying to resolve 10.0.0.254
[2020-04-08 18:00:00.844 872] Trying to resolve 127.0.0.1
[2020-04-08 18:00:00.845 872] 2 / 2 upstream server host names resolved
----------------------------------------------------------------------------------------------------------------2020/04/08 18:00:40----------------------------------------------------------------------------------------------------------------
[2020-04-08 18:01:00.409 872] 0 / 10 client host names resolved
[2020-04-08 18:01:00.409 872] 0 / 2 upstream server host names resolved
From another thread I stole the idea to switch to another FTL branch
pihole checkout ftl tweak/more_resolver_debugging
Looks like all local IP addresses are resolved to
"" (N/A)
I did setup DNS-Over-HTTPS as described here: Redirecting...
Does this interfere?
Herer is the output:
[2020-04-08 21:01:15.463 26687] Using log file /var/log/pihole-FTL.log
[2020-04-08 21:01:15.463 26687] ########## FTL started! ##########
[2020-04-08 21:01:15.463 26687] FTL branch: tweak/more_resolver_debugging
[2020-04-08 21:01:15.463 26687] FTL version: vDev-bd5749d
[2020-04-08 21:01:15.463 26687] FTL commit: bd5749d
[2020-04-08 21:01:15.463 26687] FTL date: 2020-04-08 15:10:57 +0200
[2020-04-08 21:01:15.463 26687] FTL user: pihole
[2020-04-08 21:01:15.463 26687] Compiled for armhf (compiled on CI) using arm-linux-gnueabihf-gcc (Debian 6.3.0-18) 6.3.0 20170516
[2020-04-08 21:01:15.463 26687] Starting config file parsing (/etc/pihole/pihole-FTL.conf)
[2020-04-08 21:01:15.464 26687] SOCKET_LISTENING: only local
[2020-04-08 21:01:15.464 26687] AAAA_QUERY_ANALYSIS: Show AAAA queries
[2020-04-08 21:01:15.464 26687] MAXDBDAYS: max age for stored queries is 365 days
[2020-04-08 21:01:15.464 26687] RESOLVE_IPV6: Resolve IPv6 addresses
[2020-04-08 21:01:15.464 26687] RESOLVE_IPV4: Resolve IPv4 addresses
[2020-04-08 21:01:15.464 26687] DBINTERVAL: saving to DB file every minute
[2020-04-08 21:01:15.464 26687] DBFILE: Using /etc/pihole/pihole-FTL.db
[2020-04-08 21:01:15.464 26687] MAXLOGAGE: Importing up to 24.0 hours of log data
[2020-04-08 21:01:15.464 26687] PRIVACYLEVEL: Set to 0
[2020-04-08 21:01:15.464 26687] IGNORE_LOCALHOST: Show queries from localhost
[2020-04-08 21:01:15.464 26687] BLOCKINGMODE: Null IPs for blocked domains
[2020-04-08 21:01:15.464 26687] ANALYZE_ONLY_A_AND_AAAA: Disabled. Analyzing all queries
[2020-04-08 21:01:15.464 26687] DBIMPORT: Importing history from database
[2020-04-08 21:01:15.464 26687] PIDFILE: Using /var/run/pihole-FTL.pid
[2020-04-08 21:01:15.464 26687] PORTFILE: Using /var/run/pihole-FTL.port
[2020-04-08 21:01:15.464 26687] SOCKETFILE: Using /var/run/pihole/FTL.sock
[2020-04-08 21:01:15.464 26687] SETUPVARSFILE: Using /etc/pihole/setupVars.conf
[2020-04-08 21:01:15.464 26687] MACVENDORDB: Using /etc/pihole/macvendor.db
[2020-04-08 21:01:15.464 26687] GRAVITYDB: Using /etc/pihole/gravity.db
[2020-04-08 21:01:15.465 26687] PARSE_ARP_CACHE: Active
[2020-04-08 21:01:15.465 26687] REGEX_IGNORECASE: Disabled. Regex is case sensitive
[2020-04-08 21:01:15.465 26687] CNAME_DEEP_INSPECT: Active
[2020-04-08 21:01:15.465 26687] DELAY_STARTUP: No delay requested.
[2020-04-08 21:01:15.465 26687] FORCE_FIRST_RESOLVER: Inactive
[2020-04-08 21:01:15.465 26687] *****************************
[2020-04-08 21:01:15.465 26687] * Debugging enabled *
[2020-04-08 21:01:15.465 26687] * DEBUG_DATABASE NO *
[2020-04-08 21:01:15.465 26687] * DEBUG_NETWORKING NO *
[2020-04-08 21:01:15.465 26687] * DEBUG_LOCKS NO *
[2020-04-08 21:01:15.465 26687] * DEBUG_QUERIES NO *
[2020-04-08 21:01:15.465 26687] * DEBUG_FLAGS NO *
[2020-04-08 21:01:15.465 26687] * DEBUG_SHMEM NO *
[2020-04-08 21:01:15.465 26687] * DEBUG_GC NO *
[2020-04-08 21:01:15.465 26687] * DEBUG_ARP NO *
[2020-04-08 21:01:15.465 26687] * DEBUG_REGEX NO *
[2020-04-08 21:01:15.465 26687] * DEBUG_API YES *
[2020-04-08 21:01:15.465 26687] * DEBUG_OVERTIME NO *
[2020-04-08 21:01:15.465 26687] * DEBUG_EXTBLOCKED NO *
[2020-04-08 21:01:15.465 26687] * DEBUG_CAPS NO *
[2020-04-08 21:01:15.465 26687] * DEBUG_DNSMASQ_LINES NO *
[2020-04-08 21:01:15.466 26687] * DEBUG_VECTORS NO *
[2020-04-08 21:01:15.466 26687] *****************************
[2020-04-08 21:01:15.466 26687] Finished config file parsing
[2020-04-08 21:01:15.467 26687] Database version is 5
[2020-04-08 21:01:15.467 26687] Database successfully initialized
[2020-04-08 21:01:15.468 26687] New upstream server: 10.0.0.254 (0/1024)
[2020-04-08 21:01:15.469 26687] New upstream server: 127.0.0.1 (1/1024)
[2020-04-08 21:01:15.489 26687] Resizing "/FTL-strings" from 4096 to 8192
[2020-04-08 21:01:15.504 26687] Resizing "/FTL-queries" from 229376 to 458752
[2020-04-08 21:01:15.520 26687] Resizing "/FTL-strings" from 8192 to 12288
[2020-04-08 21:01:15.522 26687] Imported 5505 queries from the long-term database
[2020-04-08 21:01:15.523 26687] -> Total DNS queries: 5505
[2020-04-08 21:01:15.523 26687] -> Cached DNS queries: 817
[2020-04-08 21:01:15.523 26687] -> Forwarded DNS queries: 2314
[2020-04-08 21:01:15.523 26687] -> Blocked DNS queries: 2374
[2020-04-08 21:01:15.523 26687] -> Unknown DNS queries: 0
[2020-04-08 21:01:15.523 26687] -> Unique domains: 349
[2020-04-08 21:01:15.523 26687] -> Unique clients: 15
[2020-04-08 21:01:15.523 26687] -> Known forward destinations: 2
[2020-04-08 21:01:15.523 26687] Successfully accessed setupVars.conf
[2020-04-08 21:01:15.523 26687] DEBUG: argv[0] = ""
[2020-04-08 21:01:15.523 26687] DEBUG: argv[1] = "-k"
[2020-04-08 21:01:15.528 26689] PID of FTL process: 26689
[2020-04-08 21:01:15.528 26689] Listening on port 4711 for incoming IPv4 telnet connections
[2020-04-08 21:01:15.529 26689] Listening on port 4711 for incoming IPv6 telnet connections
[2020-04-08 21:01:15.529 26689] Listening on Unix socket
[2020-04-08 21:01:15.532 26689] Reloading DNS cache
[2020-04-08 21:01:15.532 26689] Blocking status is enabled
[2020-04-08 21:01:15.532 26689] *****************************
[2020-04-08 21:01:15.532 26689] * Debugging enabled *
[2020-04-08 21:01:15.532 26689] * DEBUG_DATABASE NO *
[2020-04-08 21:01:15.532 26689] * DEBUG_NETWORKING NO *
[2020-04-08 21:01:15.532 26689] * DEBUG_LOCKS NO *
[2020-04-08 21:01:15.532 26689] * DEBUG_QUERIES NO *
[2020-04-08 21:01:15.532 26689] * DEBUG_FLAGS NO *
[2020-04-08 21:01:15.532 26689] * DEBUG_SHMEM NO *
[2020-04-08 21:01:15.533 26689] * DEBUG_GC NO *
[2020-04-08 21:01:15.533 26689] * DEBUG_ARP NO *
[2020-04-08 21:01:15.533 26689] * DEBUG_REGEX NO *
[2020-04-08 21:01:15.533 26689] * DEBUG_API YES *
[2020-04-08 21:01:15.533 26689] * DEBUG_OVERTIME NO *
[2020-04-08 21:01:15.533 26689] * DEBUG_EXTBLOCKED NO *
[2020-04-08 21:01:15.533 26689] * DEBUG_CAPS NO *
[2020-04-08 21:01:15.533 26689] * DEBUG_DNSMASQ_LINES NO *
[2020-04-08 21:01:15.533 26689] * DEBUG_VECTORS NO *
[2020-04-08 21:01:15.533 26689] *****************************
[2020-04-08 21:01:15.538 26689] INFO: No regex whitelist entries found
[2020-04-08 21:01:15.546 26689] Compiled 0 whitelist and 5 blacklist regex filters in 9.9 msec
[2020-04-08 21:02:00.119 26689] Trying to resolve 10.0.0.1
[2020-04-08 21:02:00.120 26689] Using resolvers (added FTL as last resolver):
[2020-04-08 21:02:00.120 26689] 0: 84.200.69.80
[2020-04-08 21:02:00.120 26689] 1: 84.200.70.40
[2020-04-08 21:02:00.120 26689] 2: 127.0.0.1
[2020-04-08 21:02:00.134 26689] ---> "" (N/A)
[2020-04-08 21:02:00.167 26689] Trying to resolve 10.0.1.89
[2020-04-08 21:02:00.168 26689] Using resolvers (added FTL as last resolver):
[2020-04-08 21:02:00.168 26689] 0: 84.200.69.80
[2020-04-08 21:02:00.168 26689] 1: 84.200.70.40
[2020-04-08 21:02:00.168 26689] 2: 127.0.0.1
[2020-04-08 21:02:00.180 26689] ---> "" (N/A)
[2020-04-08 21:02:00.182 26689] Trying to resolve 10.0.0.116
[2020-04-08 21:02:00.182 26689] Using resolvers (added FTL as last resolver):
[2020-04-08 21:02:00.182 26689] 0: 84.200.69.80
[2020-04-08 21:02:00.182 26689] 1: 84.200.70.40
[2020-04-08 21:02:00.182 26689] 2: 127.0.0.1
[2020-04-08 21:02:00.194 26689] ---> "" (N/A)
[2020-04-08 21:02:00.195 26689] Trying to resolve 10.0.1.5
[2020-04-08 21:02:00.195 26689] Using resolvers (added FTL as last resolver):
[2020-04-08 21:02:00.195 26689] 0: 84.200.69.80
[2020-04-08 21:02:00.195 26689] 1: 84.200.70.40
[2020-04-08 21:02:00.195 26689] 2: 127.0.0.1
[2020-04-08 21:02:00.207 26689] ---> "" (N/A)
[2020-04-08 21:02:00.209 26689] Trying to resolve 10.0.1.64
[2020-04-08 21:02:00.209 26689] Using resolvers (added FTL as last resolver):
[2020-04-08 21:02:00.209 26689] 0: 84.200.69.80
[2020-04-08 21:02:00.209 26689] 1: 84.200.70.40
[2020-04-08 21:02:00.209 26689] 2: 127.0.0.1
[2020-04-08 21:02:00.221 26689] ---> "" (N/A)
[2020-04-08 21:02:00.222 26689] Trying to resolve 10.0.1.65
[2020-04-08 21:02:00.222 26689] Using resolvers (added FTL as last resolver):
[2020-04-08 21:02:00.222 26689] 0: 84.200.69.80
[2020-04-08 21:02:00.223 26689] 1: 84.200.70.40
[2020-04-08 21:02:00.223 26689] 2: 127.0.0.1
[2020-04-08 21:02:00.234 26689] ---> "" (N/A)
[2020-04-08 21:02:00.236 26689] Trying to resolve ::1
[2020-04-08 21:02:00.236 26689] Using resolvers (added FTL as last resolver):
[2020-04-08 21:02:00.236 26689] 0: 84.200.69.80
[2020-04-08 21:02:00.236 26689] 1: 84.200.70.40
[2020-04-08 21:02:00.236 26689] 2: 127.0.0.1
[2020-04-08 21:02:00.236 26689] ---> "localhost" (localhost)
[2020-04-08 21:02:00.236 26689] Trying to resolve 10.0.1.44
[2020-04-08 21:02:00.236 26689] Using resolvers (added FTL as last resolver):
[2020-04-08 21:02:00.236 26689] 0: 84.200.69.80
[2020-04-08 21:02:00.236 26689] 1: 84.200.70.40
[2020-04-08 21:02:00.236 26689] 2: 127.0.0.1
[2020-04-08 21:02:00.248 26689] ---> "" (N/A)
[2020-04-08 21:02:00.250 26689] Trying to resolve 10.0.1.19
[2020-04-08 21:02:00.250 26689] Using resolvers (added FTL as last resolver):
[2020-04-08 21:02:00.250 26689] 0: 84.200.69.80
[2020-04-08 21:02:00.250 26689] 1: 84.200.70.40
[2020-04-08 21:02:00.250 26689] 2: 127.0.0.1
[2020-04-08 21:02:00.262 26689] ---> "" (N/A)
[2020-04-08 21:02:00.263 26689] Trying to resolve 10.0.1.67
[2020-04-08 21:02:00.263 26689] Using resolvers (added FTL as last resolver):
[2020-04-08 21:02:00.263 26689] 0: 84.200.69.80
[2020-04-08 21:02:00.264 26689] 1: 84.200.70.40
[2020-04-08 21:02:00.264 26689] 2: 127.0.0.1
[2020-04-08 21:02:00.275 26689] ---> "" (N/A)
[2020-04-08 21:02:00.277 26689] Trying to resolve 10.0.1.12
[2020-04-08 21:02:00.277 26689] Using resolvers (added FTL as last resolver):
[2020-04-08 21:02:00.277 26689] 0: 84.200.69.80
[2020-04-08 21:02:00.277 26689] 1: 84.200.70.40
[2020-04-08 21:02:00.277 26689] 2: 127.0.0.1
[2020-04-08 21:02:00.289 26689] ---> "" (N/A)
[2020-04-08 21:02:00.290 26689] Trying to resolve 10.0.1.6
[2020-04-08 21:02:00.290 26689] Using resolvers (added FTL as last resolver):
[2020-04-08 21:02:00.291 26689] 0: 84.200.69.80
[2020-04-08 21:02:00.291 26689] 1: 84.200.70.40
[2020-04-08 21:02:00.291 26689] 2: 127.0.0.1
[2020-04-08 21:02:00.302 26689] ---> "" (N/A)
[2020-04-08 21:02:00.304 26689] Trying to resolve 10.0.0.70
[2020-04-08 21:02:00.304 26689] Using resolvers (added FTL as last resolver):
[2020-04-08 21:02:00.304 26689] 0: 84.200.69.80
[2020-04-08 21:02:00.304 26689] 1: 84.200.70.40
[2020-04-08 21:02:00.304 26689] 2: 127.0.0.1
[2020-04-08 21:02:00.316 26689] ---> "" (N/A)
[2020-04-08 21:02:00.317 26689] Trying to resolve 10.0.0.252
[2020-04-08 21:02:00.318 26689] Using resolvers (added FTL as last resolver):
[2020-04-08 21:02:00.318 26689] 0: 84.200.69.80
[2020-04-08 21:02:00.318 26689] 1: 84.200.70.40
[2020-04-08 21:02:00.318 26689] 2: 127.0.0.1
[2020-04-08 21:02:00.330 26689] ---> "" (N/A)
[2020-04-08 21:02:00.332 26689] Trying to resolve 10.0.1.3
[2020-04-08 21:02:00.332 26689] Using resolvers (added FTL as last resolver):
[2020-04-08 21:02:00.332 26689] 0: 84.200.69.80
[2020-04-08 21:02:00.332 26689] 1: 84.200.70.40
[2020-04-08 21:02:00.332 26689] 2: 127.0.0.1
[2020-04-08 21:02:00.344 26689] ---> "" (N/A)
[2020-04-08 21:02:00.346 26689] 15 / 15 client host names resolved
[2020-04-08 21:02:00.346 26689] Trying to resolve 10.0.0.254
[2020-04-08 21:02:00.346 26689] Using resolvers (added FTL as last resolver):
[2020-04-08 21:02:00.347 26689] 0: 84.200.69.80
[2020-04-08 21:02:00.347 26689] 1: 84.200.70.40
[2020-04-08 21:02:00.347 26689] 2: 127.0.0.1
[2020-04-08 21:02:00.358 26689] ---> "" (N/A)
[2020-04-08 21:02:00.360 26689] Trying to resolve 127.0.0.1
[2020-04-08 21:02:00.360 26689] Using resolvers (added FTL as last resolver):
[2020-04-08 21:02:00.360 26689] 0: 84.200.69.80
[2020-04-08 21:02:00.361 26689] 1: 84.200.70.40
[2020-04-08 21:02:00.361 26689] 2: 127.0.0.1
[2020-04-08 21:02:00.361 26689] ---> "localhost" (localhost)
[2020-04-08 21:02:00.361 26689] 2 / 2 upstream server host names resolved
[2020-04-08 21:03:00.426 26689] 0 / 15 client host names resolved
[2020-04-08 21:03:00.426 26689] 0 / 2 upstream server host names resolved
I have DoH setup using that guide as well, does not affect resolving host names here. Just needs the router address and domain name is my understanding.
Yeah, it's rather likely you two are affected by the same bug, I'm just wondering what is causing the failure for the two of you yet none of the other numerous beta testers?
Could you try if the situation changes with
Now this is relevant:
DEBUG_RESOLVER=true
+
pihole checkout ftl tweak/resolver_try_FTL_first_then_others
(nothing else changed as suggested in you post)
works!
All my hostnames are now resolved!
I am now just wondering, do I have to add my routers/DHCP IP as "Custom 2 (IPv4)" or not?
Cheers,
Bjoern
Just tried to remove it from “Custom 2 (IPv4)” and I can't access anything on my local network by hostname and no local clients are resolved on the dashboard so it seems to be mandatory that my router/DHCP is set in “Custom 2 (IPv4)”
No, you don't need the router address here...it goes in the Settings | DNS tab.
@DL6ER Just updated and flushed my network table. Now I'm seeing "unknown" for host names for devices that do not make queries to pihole (access points, switches, etc). MAC ID / vendor data is populated, but where host name was populating it's now "unknown". FYI.
Edit (in case this helps...again this was resolving and no longer does in pihole):
pi@rpi-2:~ $ sudo dig -x 192.168.1.6 @192.168.1.1
; <<>> DiG 9.11.5-P4-5.1-Raspbian <<>> -x 192.168.1.6 @192.168.1.1
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 7425
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;6.1.168.192.in-addr.arpa. IN PTR
;; ANSWER SECTION:
6.1.168.192.in-addr.arpa. 3600 IN PTR T2600G-28TS.home.
;; Query time: 0 msec
;; SERVER: 192.168.1.1#53(192.168.1.1)
;; WHEN: Thu Apr 09 13:13:45 EDT 2020
;; MSG SIZE rcvd: 83
Well, I tried to remove it and as said, its not working with this config on the Settings | DNS tab it works fine:
Check "Use Conditional Forwarding" (bottom of page) and add your router IP and the domain name for your network (typically "local" or "home" or whatever yours is).
Indeed, this now works as well 
mine is local.mydomain.de (where mydomain is just a XXXX for my real domain name)
What was the actual issue?
And what was the actual fix?
Thanks all for figuring out this issue!
Cheers,
Bjoern
I know, there was an issue with host name resolution of clients not known to FTL. The memory issues involved were non-trivial and I figured this is not important enough to write the code for handing this (they otherwise don't get properly initialized).
OK, I thought we had it working...but agreed, not critical but nice to have. Thanks!
We had, but the latest bigger issue FTL#718 and
were both caused by this. The extras work needed to initialize clients that never sent any real DNS seemed to be too much of an edge-case to be worth the effort.
The PR has been reviewed and merged. Please go back to the main branch using
pihole checkout ftl release/v5.0
Switched back to release/v5.0 and everything is still working!
Pi-hole Version vDev (release/v5.0, v4.3.5-458-g2de5362)
Web Interface Version vDev (release/v5.0, v4.3.2-462-g8e51f75)
FTL Version vDev (release/v5.0, vDev-d395b3b)
Is this line in /etc/dnsmasq.d/05-rev-server.conf still mandatory after the fix?
rev-server=10.0.0.0/8,10.0.0.254
By the way, when I tried with 10.0.0.0/23 (this is my actual subnet mask) a dns restart failed.
Cheers,
Bjoern
Yes, if Pi-hole is not your DHCP server it will have to know which upstream to ask. You can either specify your DHCP server as regular upstream (it will then receive all queries) or use the config option above to have to receive only queries for it's subnet (much cleaner in my eyes). The embedded Conditional Forwarding functionality does only support /24 networks + the DHCP server has to be in the same subnet.
The embedded dnsmasq supports only /8, /16, /24 and /32 subnets for rev-server. This is something we cannot change easily, however, if I have a lot of surplus time and energy (not seeing this happening within the next ten years, but never say never), I may look into this again and send a patch upstream.
Thanks a lot!
Maybe it is worth to put this explanation below the "conditional forwarding" setting in the DNS settings page (or at least a note that one /24 is supported an one might want to consider adding rev-server= to /etc/dnsmasq.d/05-rev-server.conf)
This kind of dedication should be a role model for many commercial companies.
Well worth a donation: DONE!
Cheers,
Bjoern