this spec is confusing

copyparty/__main__.py

@@ -663,7 +663,7 @@ def run_argparse(
 
     ap2 = ap.add_argument_group("Zeroconf options")
     ap2.add_argument("--zm", action="store_true", help="announce the enabled protocols over mDNS (multicast DNS-SD) -- compatible with KDE, gnome, macOS, ...")
-    ap2.add_argument("--zm4", action="store_true", help="IPv4 only -- try this if some clients don't work")
+    ap2.add_argument("--zm4", action="store_true", help="IPv4 only -- try this if some clients can't connect")
     ap2.add_argument("--zm6", action="store_true", help="IPv6 only")
     ap2.add_argument("--zmv", action="store_true", help="verbose mdns")
     ap2.add_argument("--zmvv", action="store_true", help="verboser mdns")
@@ -674,6 +674,7 @@ def run_argparse(
     ap2.add_argument("--zm-ls", metavar="PATH", type=str, default="", help="link a specific folder for smb shares")
     ap2.add_argument("--zm-mnic", action="store_true", help="merge NICs which share subnets; assume that same subnet means same network")
     ap2.add_argument("--zm-msub", action="store_true", help="merge subnets on each NIC -- always enabled for ipv6 -- reduces network load, but gnome-gvfs clients may stop working")
+    ap2.add_argument("--zm-noneg", action="store_true", help="disable NSEC replies -- try this if some clients don't see copyparty")
     ap2.add_argument("--mc-hop", metavar="SEC", type=int, default=0, help="rejoin multicast groups every SEC seconds (workaround for some switches/routers which cause mDNS to suddenly stop working after some time); try [\033[32m300\033[0m] or [\033[32m180\033[0m]")
 
     ap2 = ap.add_argument_group('FTP options')

copyparty/mdns.py

@@ -175,12 +175,6 @@ class MDNS(MCast):
                 sreply.add_answer(r120)
                 bye.add_answer(r0)
 
-            if not have4 or not have6:
-                ns = NSEC(self.hn, ["AAAA" if have4 else "A"])
-                r = RR(self.hn, QTYPE.NSEC, DC.F_IN, 120, ns)
-                areply.add_ar(r)
-                sreply.add_ar(r)
-
             for sclass, props in self.svcs.items():
                 sname = props["name"]
                 sport = props["port"]
@@ -216,6 +210,14 @@ class MDNS(MCast):
                 r = RR(sfqdn, QTYPE.TXT, DC.F_IN, 4500, TXT(txts))
                 sreply.add_answer(r)
 
+            if not (have4 and have6) and not self.args.zm_noneg:
+                have = "AAAA" if have6 else "A"
+                ns = NSEC(self.hn, [have, "PTR", "SRV", "TXT"])
+                r = RR(self.hn, QTYPE.NSEC, DC.F_IN, 120, ns)
+                areply.add_ar(r)
+                if len(sreply.pack()) < 1400:
+                    sreply.add_ar(r)
+
             srv.bp_probe = probe.pack()
             srv.bp_ip = areply.pack()
             srv.bp_svc = sreply.pack()

copyparty/multicast.py

@@ -41,6 +41,8 @@ class MC_Sck(object):
         self.net = net
         self.ips = {ip: net}
         self.v6 = ":" in ip
+        self.have4 = ":" not in ip
+        self.have6 = ":" in ip
 
 
 class MCast(object):

copyparty/stolen/dnslib/dns.py

@@ -105,7 +105,7 @@ class DNSRecord(object):
         self, header=None, questions=None, rr=None, q=None, a=None, auth=None, ar=None
     ) -> None:
         self.header = header or DNSHeader()
-        self.questions = questions or []
+        self.questions: list[DNSQuestion] = questions or []
         self.rr = rr or []
         self.auth = auth or []
         self.ar = ar or []