Hi everyone, I am reaching out to seek your assistance regarding an issue I am experiencing with my DevStack installation. After successfully installing DevStack stable/2024.2 on ubuntu 22.04, I configured the network and set up DNS for private subnet. stack@controller:~$ openstack subnet list +--------------------------------------+---------------------+--------------------------------------+---------------------+ | ID | Name | Network | Subnet | +--------------------------------------+---------------------+--------------------------------------+---------------------+ | 2b6411d5-9c19-4a45-bd47-58dc748f5e00 | public-subnet | 45502b6a-773b-40cf-866a-e8b18397ffcb | 192.168.1.0/24 | | 69629170-2e0e-49c0-b741-61560558001c | ipv6-public-subnet | 45502b6a-773b-40cf-866a-e8b18397ffcb | 2001:db8::/64 | | c74bf062-b67a-45cb-8a50-73583498dfcd | ipv6-private-subnet | 8fb37e61-bd59-4624-a4be-1fc1841987d7 | fd3a:2f86:ca98::/64 | | f2e10d3d-f785-4cf9-8804-1969269623c2 | private-subnet | 8fb37e61-bd59-4624-a4be-1fc1841987d7 | 10.0.0.0/26 | +--------------------------------------+---------------------+--------------------------------------+---------------------+ stack@controller:~$ openstack subnet set --dns-nameserver 10.12.255.254 --dns-nameserver 192.168.1.95 f2e10d3d-f785-4cf9-8804-1969269623c2 10.12.255.254 is the real DNS server address and 192.168.1.95 is my server IP address. Initially, when I launched a VM instance, it was able to resolve the proxy and connect to the external network without any issues. jenkins@np0000000531:~$ curl opendev.org <a href="https://opendev.org/">Temporary Redirect</a>. However, after rebooting the server and launching the instance again, the instance is unable to resolve the proxy. jenkins@np0000000531:~$ curl opendev.org curl: (5) Could not resolve proxy: my.proxy.com I have verified that the systemd-resolved service is in an active state, but the logs show a large number of entries with the following message: Nov 13 11:53:51 np0000000531 systemd-resolved[568]: Using degraded feature set UDP instead of TCP for DNS server 10.12.255.254. Nov 13 11:54:01 np0000000531 systemd-resolved[568]: Using degraded feature set UDP instead of TCP for DNS server 192.168.1.95. Nov 13 11:54:01 np0000000531 systemd-resolved[568]: Using degraded feature set TCP instead of UDP for DNS server 10.12.255.254. Nov 13 11:54:11 np0000000531 systemd-resolved[568]: Using degraded feature set TCP instead of UDP for DNS server 192.168.1.95. Nov 13 11:54:21 np0000000531 systemd-resolved[568]: Using degraded feature set UDP instead of TCP for DNS server 10.12.255.254. I have checked the network and routing table of the VM instance, as well as the bridge settings on the server. Everything appears to be the same as it was before the reboot. Could you please help me identify the cause of this issue and suggest any potential solutions? If you need any additional information, please let me know, and I will be happy to provide it. Thank you for your time and assistance. Best regards, Inori.