<!DOCTYPE html> <html> <head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body> <div class="moz-text-html" lang="x-unicode"> Hi, I hope it’s OK to ask a question here (the About section said as much). I’m receiving messages in the journal that I have difficulty interpreting. It appears to repeatedly switch from TCP to UDP and back, claiming that both are a “degraded feature set”… Here is a sample journal output: ~$ journalctl --unit systemd-resolved.service -r | head -n 60 May 02 10:29:56 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:29:56 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:29:46 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:29:46 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:29:46 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:29:46 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:29:46 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:29:46 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:27:50 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:27:50 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:27:33 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:27:33 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:27:19 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:27:19 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:27:16 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:27:16 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:26:53 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:26:53 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:26:39 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:26:39 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:26:38 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:26:38 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:26:36 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:26:36 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:25:25 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:25:25 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:25:24 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:25:24 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:25:24 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:25:24 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:25:24 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:25:24 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:25:23 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:25:23 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:25:23 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:25:23 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:25:23 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:25:23 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:25:23 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:25:23 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:25:22 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:25:22 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:24:55 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:24:55 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:24:51 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:24:51 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:24:51 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:24:51 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:24:48 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:24:48 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:24:48 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:24:35 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of UDP+EDNS0 for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:24:35 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of UDP+EDNS0 for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:23:54 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:23:54 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:23:54 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:23:54 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:23:54 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.1.1.1#cloudflare-dns.com. May 02 10:22:56 nailbox systemd-resolved[95890]: Using degraded feature set TCP instead of UDP for DNS server 1.0.0.1#cloudflare-dns.com. May 02 10:22:56 nailbox systemd-resolved[95890]: Using degraded feature set UDP instead of TCP for DNS server 1.0.0.1#cloudflare-dns.com. Do you know if this is intended behavior? What am I supposed to make of this? Here is my /etc/systemd/resolved.conf: [Resolve] DNS=1.1.1.1#cloudflare-dns.com 1.0.0.1#cloudflare-dns.com 2606:4700:4700::1111#cloudflare-dns.com 2606:4700:4700::1001#cloudflare-dns.com LLMNR=true DNSSEC=false DNSOverTLS=false Here is the output of resolvectl status (with the local DNS redacted): Global Protocols: +LLMNR +mDNS -DNSOverTLS DNSSEC=no/unsupported resolv.conf mode: stub Current DNS Server: 1.1.1.1#cloudflare-dns.com DNS Servers: 1.1.1.1#cloudflare-dns.com 1.0.0.1#cloudflare-dns.com 2606:4700:4700::1111#cloudflare-dns.com 2606:4700:4700::1001#cloudflare-dns.com Fallback DNS Servers: 1.1.1.1#cloudflare-dns.com 8.8.8.8#dns.google 1.0.0.1#cloudflare-dns.com 8.8.4.4#dns.google 2606:4700:4700::1111#cloudflare-dns.com 2001:4860:4860::8888#dns.google 2606:4700:4700::1001#cloudflare-dns.com 2001:4860:4860::8844#dns.google Link 2 (docker0) Current Scopes: none Protocols: -DefaultRoute +LLMNR +mDNS -DNSOverTLS DNSSEC=no/unsupported Link 3 (wlp4s0) Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6 mDNS/IPv4 mDNS/IPv6 Protocols: +DefaultRoute +LLMNR +mDNS -DNSOverTLS DNSSEC=no/unsupported Current DNS Server: ███████████████ DNS Servers: ███████████████ DNS Domain: intern I’m using NixOS (24.05.20240425.7bb2ccd (Uakari)) and running systemd 255.4. Here is the output of systemctl --version: systemd 255 (255.4) +PAM +AUDIT -SELINUX +APPARMOR +IMA +SMACK +SECCOMP +GCRYPT -GNUTLS +OPENSSL +ACL +BLKID +CURL +ELFUTILS +FIDO2 +IDN2 -IDN +IPTC +KMOD +LIBCRYPTSETUP +LIBFDISK +PCRE2 +PWQUALITY +P11KIT +QRENCODE +TPM2 +BZIP2 +LZ4 +XZ +ZLIB +ZSTD +BPF_FRAMEWORK -XKBCOMMON +UTMP -SYSVINIT default-hierarchy=unified Normally I have an Autocrypt header with PGP information but I just set up this system and haven’t configured GPG/Thunderbird with that yet. Sincerely, Anselm Schüler (<a moz-do-not-send="true" href="mailto:mail@anselmschueler.com">email</a>, <a moz-do-not-send="true" href="https://anselmschueler.com/">website</a>) </div> </body> </html>