feat: mail ipv6/rdns checks and taler-ops catalog

check_mail.sh

@@ -213,12 +213,44 @@ while IFS= read -r line || [ -n "$line" ]; do
     h=$(echo "$h" | tr '[:upper:]' '[:lower:]' | sed 's/\.$//;s/^[[:space:]]*//;s/[[:space:]]*$//')
     [ -z "$h" ] && continue
 
-    addrs=$(dns_a "$h" | tr '\n' ' ')
+    mapfile -t _a4 < <(dns_a "$h" | sed '/^$/d')
+    addrs=$(printf '%s ' "${_a4[@]}")
     if [ -z "${addrs// }" ]; then
       fail "dns" "$h does not resolve (A/AAAA)"
       continue
     fi
     ok "dns" "$h → $addrs"
+    # Explicit IPv6 signal
+    _has_v4=0
+    _has_v6=0
+    for _ip in "${_a4[@]}"; do
+      case "$_ip" in
+        *:*) _has_v6=1 ;;
+        *) _has_v4=1 ;;
+      esac
+    done
+    if [ "$_has_v4" = "1" ] && [ "$_has_v6" = "0" ]; then
+      warn "ipv6" "$h has A but no AAAA"
+    elif [ "$_has_v6" = "1" ]; then
+      ok "ipv6" "$h has AAAA"
+    fi
+    # Reverse DNS (PTR) on first IPv4
+    for _ip in "${_a4[@]}"; do
+      case "$_ip" in
+        *:*) continue ;;
+      esac
+      if command -v dig >/dev/null 2>&1; then
+        ptr=$(dig +short +time=3 +tries=2 -x "$_ip" 2>/dev/null | sed 's/\.$//' | tr '\n' ' ')
+      else
+        ptr=$(host "$_ip" 2>/dev/null | awk '/domain name pointer/{print $NF}' | sed 's/\.$//' | tr '\n' ' ')
+      fi
+      if [ -n "${ptr// }" ]; then
+        ok "rdns" "$_ip PTR → $ptr"
+      else
+        warn "rdns" "$_ip has no PTR"
+      fi
+      break
+    done
 
     # skip full protocol re-probe if already done
     if [ "${HOST_DONE[$h]:-}" = "1" ]; then