I am at a bit of a loss. I am able to perform an nslookup and a dig on the address "imap.comcast.net" but if I try to ping it or connect to it from my application I get a "Temporary failure in name resolution". Something must be amiss in my DNS configuration but I am unsure what it is.
> ping imap.comcast.net ping: imap.comcast.net: Temporary failure in name resolution > systemd-resolve --status --no-pager 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 (ens3) Current Scopes: DNS LLMNR setting: yes MulticastDNS setting: no DNSSEC setting: no DNSSEC supported: no DNS Servers: 10.0.0.2 DNS Domain: ec2.internal > cat /etc/resolv.conf # This file is managed by man:systemd-resolved(8). Do not edit. # # This is a dynamic resolv.conf file for connecting local clients to the # internal DNS stub resolver of systemd-resolved. This file lists all # configured search domains. # # Run "systemd-resolve --status" to see details about the uplink DNS servers # currently in use. # # Third party programs must not access this file directly, but only through the # symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a different way, # replace this symlink by a static file or a different symlink. # # See man:systemd-resolved.service(8) for details about the supported modes of # operation for /etc/resolv.conf. nameserver 127.0.0.53 search ec2.internal Some more forensic information /etc/resolv.conf is a symlink as seen here
> readlink -f /etc/resolv.conf /run/systemd/resolve/stub-resolv.conf If I change the symlink and restart systemd.resolve I can ping the address but it appears to disable dns caching
>sudo service systemd-resolved stop >sudo rm -f /etc/resolv.conf >sudo ln -s /run/systemd/resolve/resolv.conf /etc/resolv.conf >sudo service systemd-resolved start >ping imap.comcast.net >sudo systemd-resolve --statistics DNSSEC supported by current servers: no Transactions Current Transactions: 0 Total Transactions: 0 Cache Current Cache Size: 0 Cache Hits: 0 Cache Misses: 0 DNSSEC Verdicts Secure: 0 Insecure: 0 Bogus: 0 Indeterminate: 0 4 Answers
I think I had this issue before. I used the first answer in this question to resolve it: Wrong nameserver set by resolvconf and NetworkManager
The answer is to change the resolv.conf symlink:
sudo rm -f /etc/resolv.conf sudo ln -s /run/systemd/resolve/resolv.conf /etc/resolv.conf reboot For me the answer was that the DNS entries were missing in my Netpan setup. I edited them manually (in my case /etc/netplan/50-cloud-init.yaml but I realize that this might be specific to my environment, and might not "stick").
I changed
network: ethernets: ens160: addresses: - 10.8.25.116/28 dhcp4: false gateway4: 10.8.25.113 nameservers: addresses: [] search: [] version: 2 to
network: ethernets: ens160: addresses: - 10.8.25.116/28 dhcp4: false gateway4: 10.8.25.113 nameservers: addresses: [8.8.8.8,4.2.2.2] search: [] version: 2 and then applied it using
netplan apply It may seem crazy ... But after a LONG study of the logs, similar situations on the Internet ... It is banal for me helped - updating the packages!
Specifically, these commands:
systemctl disable systemd-resolved systemctl stop systemd-resolved reboot apt update && apt upgrade reboot systemctl enable systemd-resolved systemctl start systemd-resolved In particular, I think the systemd package was somehow corrupted ...
PS: Do not try to solve the problem with your forehead right away! Update / reinstall packages first! Save your time ;-)
I just had this issue and it drove me bananas. I checked the DNS and all the local host networking. it was all perfect. There were NO misconfigurations in the host networking: comparative analysis of other hosts which had the same config were working, but this host wasn't. Why?!?!?
The answer was a duff NAT rule in the Internet GW.
<facepalm>The DNS error message was a SYMPTOM of the problem, not the actual problem itself.</facepalm>
A quick check for missing or incorrect NAT rules in your Internet GW could save you a lot of wasted time...
