From dabe335b06145f39ea36f4841459cbf5c213be14 Mon Sep 17 00:00:00 2001
From: Fynn Godau
Date: Sun, 28 Dec 2025 17:38:40 +0000
Subject: bahnhof-dns: improved configuration options

---
 app/BahnhofDNS.hs | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/app/BahnhofDNS.hs b/app/BahnhofDNS.hs
index 1b06dc1..b4f1988 100644
--- a/app/BahnhofDNS.hs
+++ b/app/BahnhofDNS.hs
@@ -11,9 +11,19 @@ import           Util
 mkByteString :: String -> ByteString
 mkByteString = TSE.encodeUtf8 . Data.Text.pack
 
+-- | name that the nameserver will run on
 ourName :: ByteString
 ourName = mkByteString "ns.fynngodau.de."
 
+-- |
+-- Nothing to bind anywhere (*:53)
+-- recommended: set to your public IP address if running in parallel to a proper local resolver
+bindAddress :: Maybe String
+bindAddress = Just "2003:a:1525:3967::2"
+
+bindPort :: String
+bindPort = "53"
+
 servedName :: ByteString
 servedName = mkByteString "bahnhof.fynngodau.de."
 
@@ -26,6 +36,7 @@ soa = ResourceRecord servedName SOA classIN 86400 $ RD_SOA
   7200                                -- retry
   3600000                             -- expire
   3600                                -- minttl
+-- CONFIGURE UP TO HERE --
 
 ns :: ResourceRecord
 ns = ResourceRecord servedName NS classIN 86400 $ RD_NS ourName
@@ -34,10 +45,10 @@ ns = ResourceRecord servedName NS classIN 86400 $ RD_NS ourName
 main :: IO ()
 main = do -- general structure like sample code at https://book.realworldhaskell.org/read/sockets-and-syslog.html (for UDP server)
   staticData <- readData
-  addr : _ <- getAddrInfo (Just defaultHints { addrSocketType = Datagram, addrFamily = AF_INET6, addrFlags = [AI_PASSIVE] }) Nothing (Just "5300")
+  addr : _ <- getAddrInfo (Just defaultHints { addrSocketType = Datagram, addrFlags = [AI_PASSIVE] }) bindAddress (Just bindPort)
   sckt <- openSocket addr
   bind sckt (addrAddress addr)
-  putStrLn "Starting DNS server (listening on port 5300)"
+  putStrLn $ "Starting DNS server (listening on port " ++ bindPort ++ ")"
   procMessages staticData sckt
   where
     procMessages staticData sckt = do
-- 
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