Discussion:
DNS problem
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jp
2021-03-02 00:01:33 UTC
Permalink
Hello,

I have just upgraded from 16.04 to 18.04 and I experiment some
configuration problems. My server is reachable. The web site is ok. I
can connect with ssh. The problem is that I can't reach internet from
the server.

When I ping I obtain this: ping: yahoo.com: Temporary failure in name
resolution, and I am unable to udate and upgrade my system.

systemd-resolve --status | grep 'DNS Servers' -A2 do nothing. The
/etc/netplan folder is empty and netplan generate and netplan apply do
nothing.

Anyone have an idea what is wrong? It sounds like I haven't DNS but I
don't know how to setup one. I have tried to put a file named
01-network-manager-all.yalm in /etc/netplan folder. The file contains:

network:
ethernets:
eth0:
addresses: [MYSERVER_IP/24]
gateway4: GATEWAY_IP
nameservers:
addresses: [8.8.8.8, 8.8.4.4]
dhcp4: false
dhcp6: false
version: 2

and this make my server unreachable.

Then I do:

***@moonbeat:/etc/netplan# 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 (eth0)
Current Scopes: DNS
LLMNR setting: yes
MulticastDNS setting: no
DNSSEC setting: no
DNSSEC supported: no
DNS Servers: 8.8.8.8
8.8.4.4

I must delete this file in emergency to make the server reachable again.
How can I retrieve my defaults DNS, those I had under 16.04? So I will
be able to update my system.

Thanks in advance.
Andrei Z.
2021-03-02 05:28:26 UTC
Permalink
Post by jp
Hello,
I have just upgraded from 16.04 to 18.04 and I experiment some
configuration problems. My server is reachable. The web site is ok. I
can connect with ssh. The problem is that I can't reach internet from
the server.
When I ping I obtain this: ping: yahoo.com: Temporary failure in name
resolution, and I am unable to udate and upgrade my system.
systemd-resolve --status | grep 'DNS Servers' -A2 do nothing. The
/etc/netplan folder is empty and netplan generate and netplan apply do
nothing.
<snip>
Post by jp
How can I retrieve my defaults DNS, those I had under 16.04? So I will
be able to update my system.
Thanks in advance.
networking - DNS Not Working - Ask Ubuntu
https://askubuntu.com/questions/551925/dns-not-working

Newest 'server+18.04+dns' Questions - Ask Ubuntu
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