From 7ac4e3b6cf600f360592a56eb8ae53d699de1616 Mon Sep 17 00:00:00 2001
From: Joe Mou <dev@mou.fo>
Date: Sat, 15 Jun 2024 03:15:21 -0400
Subject: Remove poor IPv6 support from dynamic DNS

---
 hostnix/elmo/dyndns.nix | 13 ++-----------
 hostnix/elmo/system.nix |  3 ---
 2 files changed, 2 insertions(+), 14 deletions(-)

(limited to 'hostnix/elmo')

diff --git a/hostnix/elmo/dyndns.nix b/hostnix/elmo/dyndns.nix
index 33ce19d..750f644 100644
--- a/hostnix/elmo/dyndns.nix
+++ b/hostnix/elmo/dyndns.nix
@@ -22,6 +22,7 @@
     '';
   };
 
+  # Unused with authoritative DNS on the router. We leave it for redundancy.
   systemd.services.dyndns = {
     requires = [ "network-online.target" ];
     after = [ "network-online.target" ];
@@ -52,22 +53,12 @@
         exit 100
       fi
 
-      # Follow some RFC 6724 default address guidance, excluding ULA.
-      # It might be more robust to bind a public source socket (RFC 5014).
-      IP6=`ip -6 address show scope global -deprecated | awk -F'[ /]+' '$2 == "inet6" && $3 !~ /^f[cd]/ { print $3; exit }'`
-
       OLDIP4=`dig +short @popfresh.mou.fo $RR A 2> /dev/null`
-      OLDIP6=`dig +short @popfresh.mou.fo $RR AAAA 2> /dev/null`
-      # [ "x$IP" = "x$OLDIP4" ] && exit 0  # no update
-      if [ "x$IP4" = "x$OLDIP4" -a "x$IP6" = "x$OLDIP6" ]; then
-        exit 0
-      fi
+      [ "x$IP4" = "x$OLDIP4" ] && exit 0  # no update
 
       nsupdate -v -k /var/secrets/dyndns/`< /var/secrets/dyndns/basename`.private <<.
       update delete $RR. A
       update add $RR. 300 A $IP4
-      update delete $RR. AAAA
-      ''${IP6:+update add $RR. 300 AAAA $IP6}
       update delete $RR. TXT
       update add $RR. 300 TXT "v=spf1 include:_spf.mou.fo ~all"
       send
diff --git a/hostnix/elmo/system.nix b/hostnix/elmo/system.nix
index f1464dc..869a1db 100644
--- a/hostnix/elmo/system.nix
+++ b/hostnix/elmo/system.nix
@@ -13,9 +13,6 @@
 
   # TODO switch to networkd
   networking.networkmanager.enable = true;
-  # Temp addresses are preferred for IPv6 source address selection (RFC 6724),
-  # which complicates dynamic DNS.
-  networking.tempAddresses = "disabled";
 
   services.avahi = {
     enable = true;
-- 
cgit v1.3.1