<div dir="ltr">Hello systemd-devel group. I have just started using systemd-resolved to try and achieve a goal that I will try to explain. I know very little about it (web searches so far) so please excuse any silly questions or trains of thought. I have a Debian Bullseye client in a Microsoft network that uses a .local domain. I know that this is a bad policy, but there is nothing I can do about it. I have no choice or authority in this matter. This is how they have configured their whole environment. I have read here [ <a href="https://github.com/systemd/systemd/issues/8852">https://github.com/systemd/systemd/issues/8852</a> ] that .local can be used. At times there is complete isolation from the 4 Domain DNS servers and I want my client machine to still be able to resolve DNS entries (specifically SRV records with included A records) during this outage. I thought that systemd-resolved could cache the DNS entries and retain them until any of the DNS Servers returned to service. This only seems to happen for a short time after the outage. After some time ( I don't know how to tell how long) the entries seem to drop from cache. I would ideally like the entries to stay in cache until updated from DNS Server again (once one returns to service). On the SRV point: How can I be sure that it caches the full result of the SRV query? Eg: SRV gives 2 x A-records which then need to resolve to 2xIP-addresses. I'm not sure of the mailing lists policy for including config samples of logs, so I will include it here in email and see what happens. Please excuse if this is too much or too little information. root@VATCPCOMMLC1:~# cat /etc/systemd/resolved.conf [Resolve] DNS= 10.24.1.135 10.24.129.135 10.24.1.136 10.24.129.136 #FallbackDNS= Domains=itsvic.local #DNSSEC=no #DNSOverTLS=no #MulticastDNS=yes #LLMNR=yes #Cache=yes DNSStubListener=yes #DNSStubListenerExtra= #ReadEtcHosts=yes #ResolveUnicastSingleLabel=no root@VATCPCOMMLC1:~# root@VATCPCOMMLC1:~# ls -l /etc/resolv.conf lrwxrwxrwx 1 root root 39 Jul 30 14:11 /etc/resolv.conf -> ../run/systemd/resolve/stub-resolv.conf root@VATCPCOMMLC1:~# root@VATCPCOMMLC1:~# cat ../run/systemd/resolve/stub-resolv.conf nameserver 127.0.0.53 options edns0 trust-ad search itsvic.local root@VATCPCOMMLC1:~# root@VATCPCOMMLC1:~# cat /etc/nsswitch.conf # /etc/nsswitch.conf passwd: files systemd group: files systemd shadow: files gshadow: files hosts: files dns networks: files protocols: db files services: db files ethers: db files rpc: db files netgroup: nis root@VATCPCOMMLC1:~# root@VATCPCOMMLC1:~# resolvectl statusresolvectl status Global Protocols: +LLMNR +mDNS -DNSOverTLS DNSSEC=no/unsupported resolv.conf mode: stub Current DNS Server: 10.24.1.135 DNS Servers: 10.24.1.135 10.24.129.135 10.24.1.136 10.24.129.136 DNS Domain: itsvic.local Link 2 (ens192) Current Scopes: none Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported Link 3 (ens224) Current Scopes: none Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported Link 4 (bond0) Current Scopes: LLMNR/IPv4 LLMNR/IPv6 Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported root@VATCPCOMMLC1:~# dig srv _sip._tcp.osvsig-mets-prod.voip.itsvic.local dig srv _sip._tcp.osvsig-mets-prod.voip.itsvic.local ; <<>> DiG 9.16.48-Debian <<>> srv _sip._tcp.osvsig-mets-prod.voip.itsvic.local ;; global options: +cmd ;; Got answer: ;; WARNING: .local is reserved for Multicast DNS ;; You are currently testing what happens when an mDNS query is leaked to DNS ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 57884 ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 65494 ;; QUESTION SECTION: ;_sip._tcp.osvsig-mets-prod.voip.itsvic.local. IN SRV ;; ANSWER SECTION: _sip._tcp.osvsig-mets-prod.voip.itsvic.local. 3600 IN SRV 20 0 5060 osvn2-mets-prod.voip.itsvic.local. _sip._tcp.osvsig-mets-prod.voip.itsvic.local. 3600 IN SRV 10 0 5060 osvn1-mets-prod.voip.itsvic.local. ;; Query time: 0 msec ;; SERVER: 127.0.0.53#53(127.0.0.53) ;; WHEN: Tue Jul 30 15:38:47 AEST 2024 ;; MSG SIZE rcvd: 179 Thanks for any help.</div>