diff --git a/librewolf.cfg b/librewolf.cfg
index 16b222d..828aeaf 100644
--- a/librewolf.cfg
+++ b/librewolf.cfg
@@ -291,6 +291,7 @@ defaultPref("media.peerconnection.ice.no_host", true);
 lockPref("network.trr.mode", 5);
 lockPref("network.trr.bootstrapAddress", "");
 lockPref("network.trr.uri", "");
+lockPref("network.trr.send_user-agent_headers", false);
 lockPref("network.dns.disableIPv6", true);
 lockPref("network.dns.disablePrefetch", true);
 lockPref("network.dns.disablePrefetchFromHTTPS", true);