I'm running into a DNS issue in our office's network. We had a power outage and when the router rebooted a few of the servers on our network started to have problems connecting to other devices on the network.
All our servers are using Ubuntu 20.04 and are set to DHCP. We don't alter any network settings on these either. This is the second time this has happened, the first it fixed itself after a few hours. I'm trying to determine the root cause to prevent this from happening again. A majority of our servers are fine, this is just on 7 of them. All of our servers are on the same subnet too.
These servers cannot ping anything in the LAN including the router. It will not ping google.com, but it can reach 8.8.8.8. If I change their netplan yaml to use a public DNS like google the issue resolves itself, but I'd like to avoid doing that to all of our devices as a permanent solution. Any ideas on what could be causing this?
lsb_release -a
Distributor ID: Ubuntu
Description: Ubuntu 20.04.6 LTS
Release: 20.04
Codename: focal
cat /etc/netplan/*.yaml
network:
ethernets:
eno1:
dhcp4: true
enp3s0:
dhcp4: true
enp5s0:
dhcp4: true
version: 2
ifconfig -a
docker0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 172.17.0.1 netmask 255.255.0.0 broadcast 172.17.255.255
ether 02:42:c7:32:42:55 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
eno1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.0.40 netmask 255.255.255.0 broadcast 192.168.0.255
inet6 fe80::2be:43ff:fe9f:69d5 prefixlen 64 scopeid 0x20<link>
ether 00:be:43:9f:69:d5 txqueuelen 1000 (Ethernet)
RX packets 55032 bytes 12198105 (12.1 MB)
RX errors 0 dropped 62 overruns 0 frame 0
TX packets 14856 bytes 2663136 (2.6 MB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
device interrupt 16 memory 0xa4100000-a4120000
enp3s0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
ether 00:be:43:9f:69:d6 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
enp5s0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
ether 50:7c:6f:5d:05:f9 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
device memory 0xa4b00000-a4bfffff
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 7931 bytes 816614 (816.6 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 7931 bytes 816614 (816.6 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
tailscale0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST> mtu 1280
inet 100.96.215.19 netmask 255.255.255.255 destination 100.96.215.19
inet6 fe80::2af2:5a40:4399:cbd prefixlen 64 scopeid 0x20<link>
inet6 fd7a:115c:a1e0::6b01:d713 prefixlen 128 scopeid 0x0<global>
unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 500 (UNSPEC)
RX packets 2724 bytes 222118 (222.1 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 6047 bytes 845973 (845.9 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ping -c 5 google.com
ping: google.com: Temporary failure in name resolution
ping -c 5 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=53 time=2.39 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=53 time=2.64 ms
64 bytes from 8.8.8.8: icmp_seq=3 ttl=53 time=2.53 ms
64 bytes from 8.8.8.8: icmp_seq=4 ttl=53 time=2.61 ms
64 bytes from 8.8.8.8: icmp_seq=5 ttl=53 time=2.61 ms
--- 8.8.8.8 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4008ms
rtt min/avg/max/mdev = 2.393/2.557/2.644/0.090 ms
nslookup google.com
Server: 127.0.0.53
Address: 127.0.0.53#53
** server can't find google.com: SERVFAIL
