My Custom DNS-Server is randomly not queried anymore.
I am using Ubuntu 18.04 and I have my own DNS server in my network. I set up my dhcp server to set up that DNS server for the network. Before I had set up my DNS server explicitly, but now I am visiting two wifi access points and the second one doesn't have that DNS server.
Now I have deleted the
nameservers section from my netplan yaml file, because I can't seem to set it on a per AP basis.
After a reconnect everything works fine for a while, but then suddenly the DNS server doesn't answer anymore for anything in my lan, but public stuff like google works fine.
When I reconnect then, it works again for a while, and then seemingly randomly stops.
dig with the dns server explicitly works fine.
I am confused, dig says the response comes from the systemd-resolved resolver on 127.0.0.53. However the output of
systemd-resolved --status reports the correct dns server settings for my interface.
Global DNSSEC NTA: 10.in-addr.arpa 16.172.in-addr.arpa 168.192.in-addr.arpa 17.172.in-addr.arpa 18.172.in-addr.arpa 19.172.in-addr.arpa 20.172.in-addr.arpa 21.172.in-addr.arpa 22.172.in-addr.arpa 23.172.in-addr.arpa 24.172.in-addr.arpa 25.172.in-addr.arpa 26.172.in-addr.arpa 27.172.in-addr.arpa 28.172.in-addr.arpa 29.172.in-addr.arpa 30.172.in-addr.arpa 31.172.in-addr.arpa corp d.f.ip6.arpa home internal intranet lan local private test Link 4 (tun0) <OpenVPN not in use> Link 3 (wlp1s0) Current Scopes: DNS LLMNR setting: yes MulticastDNS setting: no DNSSEC setting: no DNSSEC supported: no DNS Servers: 192.168.1.5 <ipv6> DNS Domain: ~. lan Link 2 (enp2s0) <not in use>
Setting the DNS IP for the interface in netplan via
nameservers: addressess: [my.local.dns.server] search: [lan]
works fine, but again I can't do that anymore because i visit multiple access points and a configuration per access point seems impossible at the moment.
Setting the DNS server in network manager on it's own connection works fine, also.
I find this rather frustrating and want to know what DNS server I am using and why my own one isn't used anymore at random, and also why it comes back at random. I disabled DHCP on my fritzbox, it acts as a DNS server, but shouldn't be used (my own dns server uses it after 184.108.40.206 and 220.127.116.11).
# [comment block about this being systemd-dnsresolv stub] nameserver 127.0.0.53 options edns0 search lan
passwd: compat systemd group: compat systemd shadow: compat gshadow: files hosts: files mdns4_minimal [NOTFOUND=return] dns myhostname networks: files protocols: db files services: db files ethers: db files rpc: db files netgroup: nis
127.0.0.1 localhost 127.0.1.1 <myhostname>.lan <myhostname> ::1 localhost ip6-localhost ip6-loopback ff02::1 ip6-allnodes ff02::2 ip6-allrouters
I had a look with wireshark when I ran
dig. DNS queries were sent out to an ipv6 address, not my local dns server. The IPv6 Address was that of my router. Why is that?
My current netplan config:
network: version: 2 renderer: NetworkManager ethernets: enp2s0: dhcp4: yes dhcp6: yes wifis: wlp1s0: dhcp4: yes dhcp6: yes dhcp-identifier: mac access-points: "SSID1": password: **** "SSID2": password: ****