infra/modules/networking.nix
teutat3s d5922ff2b8
fix: disable DNSSEC for now because of an issue in
systemd https://github.com/systemd/systemd/issues/10579

Without this change, there are random SERVFAIL responses with Greenbaum DNS
when using allow-downgrade. Fixes DNS queries for lev-1.int.greenbaum.zone

❯ dig obs-portal.svc.e5756d08-36fd-424b-f8bc-acdb92ca7b82.lev-1.int.greenbaum.zone

; <<>> DiG 9.18.19 <<>> obs-portal.svc.e5756d08-36fd-424b-f8bc-acdb92ca7b82.lev-1.int.greenbaum.zone
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 1871
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;obs-portal.svc.e5756d08-36fd-424b-f8bc-acdb92ca7b82.lev-1.int.greenbaum.zone. IN A

;; ANSWER SECTION:
obs-portal.svc.e5756d08-36fd-424b-f8bc-acdb92ca7b82.lev-1.int.greenbaum.zone. 22 IN A 192.168.128.82

;; Query time: 105 msec
;; SERVER: 127.0.0.53#53(127.0.0.53) (UDP)
;; WHEN: Thu Nov 09 10:38:02 UTC 2023
;; MSG SIZE  rcvd: 121
2023-11-15 18:54:32 +00:00

41 lines
1.5 KiB
Nix

{ pkgs, ... }: {
services.openssh = {
enable = true;
settings = {
PermitRootLogin = "prohibit-password";
PasswordAuthentication = false;
# Add back openssh MACs that got removed from defaults
# for backwards compatibility
#
# NixOS default openssh MACs have changed to use "encrypt-then-mac" only.
# This breaks compatibilty with clients that do not offer these MACs. For
# compatibility reasons, we add back the old defaults.
# See: https://github.com/NixOS/nixpkgs/pull/231165
#
# https://blog.stribik.technology/2015/01/04/secure-secure-shell.html
# https://infosec.mozilla.org/guidelines/openssh#modern-openssh-67
Macs = [
"hmac-sha2-512-etm@openssh.com"
"hmac-sha2-256-etm@openssh.com"
"umac-128-etm@openssh.com"
"hmac-sha2-512"
"hmac-sha2-256"
"umac-128@openssh.com"
];
};
};
services.resolved = {
enable = true;
# DNSSEC=false because of random SERVFAIL responses with Greenbaum DNS
# when using allow-downgrade, see https://github.com/systemd/systemd/issues/10579
extraConfig = ''
DNS=193.110.81.0#dns0.eu 185.253.5.0#dns0.eu 2a0f:fc80::#dns0.eu 2a0f:fc81::#dns0.eu 9.9.9.9#dns.quad9.net 149.112.112.112#dns.quad9.net 2620:fe::fe#dns.quad9.net 2620:fe::9#dns.quad9.net
FallbackDNS=5.1.66.255#dot.ffmuc.net 185.150.99.255#dot.ffmuc.net 2001:678:e68:f000::#dot.ffmuc.net 2001:678:ed0:f000::#dot.ffmuc.net
Domains=~.
DNSOverTLS=yes
DNSSEC=false
'';
};
}