--- a/plugins/mod_s2s.lua	Thu Apr 02 20:54:46 2026 +0100
+++ b/plugins/mod_s2s.lua	Fri Apr 17 14:35:32 2026 +0100
@@ -41,7 +41,9 @@
 local secure_domains, insecure_domains =
 	module:get_option_set("s2s_secure_domains", {})._items, module:get_option_set("s2s_insecure_domains", {})._items;
 local require_encryption = module:get_option_boolean("s2s_require_encryption", true);
-local stanza_size_limit = module:get_option_integer("s2s_stanza_size_limit", 1024*512, 10000);
+local unauthed_stanza_size_limit = module:get_option_integer("s2s_unauthed_stanza_size_limit", 10000, 1000);
+local authed_stanza_size_limit = module:get_option_integer("s2s_stanza_size_limit", 1024*512, 10000);
+local max_child_elements = module:get_option_integer("s2s_max_child_elements", 25000, 0);
 local sendq_size = module:get_option_integer("s2s_send_queue_size", 1024*32, 1);
 local block_retries = module:get_option_boolean("s2s_block_immediate_retries", false);
 
@@ -247,6 +249,8 @@
 	end
 	host_session.version = 1;
 
+	host_session.stanza_size_limit = unauthed_stanza_size_limit;
+
 	-- Store in buffer
 	host_session.bounce_sendq = bounce_sendq;
 	host_session.sendq = queue.new(sendq_size);
@@ -291,10 +295,11 @@
 	module:hook("route/remote", route_to_existing_session, -1);
 	module:hook("route/remote", route_to_new_session, -10);
 	module:hook("s2sout-stream-features", function (event)
-		if not (stanza_size_limit or advertised_idle_timeout) then return end
+		local session = event.origin;
+		if not (session.stanza_size_limit or advertised_idle_timeout) then return end
 		local limits = event.features:tag("limits", { xmlns = "urn:xmpp:stream-limits:0" })
-		if stanza_size_limit then
-			limits:text_tag("max-bytes", string.format("%d", stanza_size_limit));
+		if session.stanza_size_limit then
+			limits:text_tag("max-bytes", string.format("%d", session.stanza_size_limit));
 		end
 		if advertised_idle_timeout then
 			limits:text_tag("idle-seconds", string.format("%d", advertised_idle_timeout));
@@ -436,6 +441,9 @@
 		return false;
 	end
 
+	session.stanza_size_limit = authed_stanza_size_limit;
+	session.stream:set_stanza_size_limit(session.stanza_size_limit);
+
 	if session.incoming and host then
 		if not session.hosts[host] then session.hosts[host] = {}; end
 		session.hosts[host].authed = true;
@@ -594,11 +602,11 @@
 			end
 
 			if ( session.type == "s2sin" or session.type == "s2sout" ) or features.tags[1] then
-				if stanza_size_limit or advertised_idle_timeout then
+				if session.stanza_size_limit or advertised_idle_timeout then
 					features:reset();
 					local limits = features:tag("limits", { xmlns = "urn:xmpp:stream-limits:0" });
-					if stanza_size_limit then
-						limits:text_tag("max-bytes", string.format("%d", stanza_size_limit));
+					if session.stanza_size_limit then
+						limits:text_tag("max-bytes", string.format("%d", session.stanza_size_limit));
 					end
 					if advertised_idle_timeout then
 						limits:text_tag("idle-seconds", string.format("%d", advertised_idle_timeout));
@@ -815,7 +823,9 @@
 
 -- Session initialization logic shared by incoming and outgoing
 local function initialize_session(session)
-	local stream = new_xmpp_stream(session, stream_callbacks, stanza_size_limit);
+	local stream = new_xmpp_stream(session, stream_callbacks, session.stanza_size_limit, {
+		max_elements = max_child_elements;
+	});
 
 	session.thread = runner(function (item)
 		if st.is_stanza(item) then
@@ -933,7 +943,7 @@
 		module:fire_event("s2sout-connected", { session = session })
 		session:open_stream(session.from_host, session.to_host);
 	end
-	module:fire_event("s2s-connected", { session = session })
+	module:fire_event("s2s-connected", { session = session, conn = conn })
 	session.ip = conn:ip();
 end