I have an ubuntu 18.04 server running apache/mysql that can't seem to resolve DNS anymore.
I didn't do anything, but maybe I missed something when checking the server after the last update.
Here's the issue:
Everything runs fine, but I can't resolve DNS (on my website as well as via SSH). For example I can't run sudo apt-get update . I get the error Could not resolve 'archive.ubuntu.com'
Here's what I already tried:
symlink fix for /etc/resolv.conf:
sudo rm /etc/resolv.conf
sudo ln -s /var/run/systemd/resolve/resolv.conf /etc/resolv.conf
didn't work.
I realized that resolvconf wasn't installed, so I installed the .deb package manually (as I can't install via apt because of the DNS issue)
didn't work.
I tried messing with the nameservers in the /etc/resolv.conf and /var/run/systemd/resolve/resolv.conf, putting nameserver 8.8.8.8
didn't work.
when I ping 8.8.8.8 I don't get anything back (I can talk to 8.8.8.8, but get 100% packet loss). But this issue might also be a firewall issue. The server is behind a strict firewall to which I don't have access to. But HTTP, HTTPS, NTP, SMTP, DNS are all allowed.
//edit5: ping is blocked by the firewall. so no surprises there.
Currently, my resolv.conf looks like this:
nameserver 127.0.0.53
nameserver 8.8.8.8
any suggestions would be very much appreciated! thanks!!
here's the output of systemd-resolve --status
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 2 (ens192)
Current Scopes: DNS
LLMNR setting: yes
MulticastDNS setting: no
DNSSEC setting: no
DNSSEC supported: no
DNS Servers: 8.8.8.8
//edit:
nslookup archive.ubuntu.com 8.8.8.8
throws
;; connection timed out; no servers could be reached
/etc/netplan/50-cloud-init.yaml contents:
network:
ethernets:
ens192:
addresses:
- 192.168.10.16/24
gateway4: 192.168.10.1
nameservers:
addresses:
- 8.8.8.8
version: 2
//edit2:
then:
nc -v -C 8.8.8.8 53
gives me a timeout:
nc: connect to 8.8.8.8 port 53 (tcp) failed: Connection timed out
also
nc -v -C 192.168.10.1 53
nc -v -C 8.8.8.8 853
have timeouts
//edit3
netstat -nr
shows
Destination Gateway Genmask Flags MSS Window irtt Iface
0.0.0.0 192.168.10.1 0.0.0.0 UG 0 0 0 ens192
192.168.10.0 0.0.0.0 255.255.255.0 U 0 0 0 ens192
//edit4
is it weird that netstat -a shows 127.0.0.53:domain ?
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:netbios-ssn 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.53:domain 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:ssh 0.0.0.0:* LISTEN
tcp 0 0 localhost.localdoma:ipp 0.0.0.0:* LISTEN