diff --git a/NEWS b/NEWS
index 614c600..43e0363 100644
--- a/NEWS
+++ b/NEWS
@@ -15,6 +15,8 @@
 
  * degesch: made "/help /command" work the same way as "/help command" does
 
+ * degesch: /ban and /unban don't mangle extended bans anymore
+
  * censor.lua: now stripping colours from censored messages;
    their attributes are also configurable rather than always black on black
 
diff --git a/degesch.c b/degesch.c
index f556241..fb3cee3 100644
--- a/degesch.c
+++ b/degesch.c
@@ -1733,6 +1733,9 @@ struct server
 	char *irc_idchan_prefixes;          ///< Prefixes for "safe channels"
 	char *irc_statusmsg;                ///< Prefixes for channel targets
 
+	char irc_extban_prefix;             ///< EXTBAN prefix or \0
+	char *irc_extban_types;             ///< EXTBAN types
+
 	char *irc_chanmodes_list;           ///< Channel modes for lists
 	char *irc_chanmodes_param_always;   ///< Channel modes with mandatory param
 	char *irc_chanmodes_param_when_set; ///< Channel modes with param when set
@@ -1781,6 +1784,9 @@ server_init_specifics (struct server *self)
 	self->irc_idchan_prefixes           = xstrdup ("");
 	self->irc_statusmsg                 = xstrdup ("");
 
+	self->irc_extban_prefix             = 0;
+	self->irc_extban_types              = xstrdup ("");
+
 	self->irc_chanmodes_list            = xstrdup ("b");
 	self->irc_chanmodes_param_always    = xstrdup ("k");
 	self->irc_chanmodes_param_when_set  = xstrdup ("l");
@@ -1799,6 +1805,8 @@ server_free_specifics (struct server *self)
 	free (self->irc_idchan_prefixes);
 	free (self->irc_statusmsg);
 
+	free (self->irc_extban_types);
+
 	free (self->irc_chanmodes_list);
 	free (self->irc_chanmodes_param_always);
 	free (self->irc_chanmodes_param_when_set);
@@ -3039,6 +3047,20 @@ irc_skip_statusmsg (struct server *s, const char *target)
 	return target + (*target && strchr (s->irc_statusmsg, *target));
 }
 
+static bool
+irc_is_extban (struct server *s, const char *target)
+{
+	// Some servers have a prefix, and some support negation
+	if (s->irc_extban_prefix && *target++ != s->irc_extban_prefix)
+		return false;
+	if (*target == '~')
+		target++;
+
+	// XXX: we don't know if it's supposed to have an argument, or not
+	return *target && strchr (s->irc_extban_types, *target++)
+		&& strchr (":\0", *target);
+}
+
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
 // As of 2020, everything should be in UTF-8.  And if it's not, we'll decode it
@@ -7926,6 +7948,16 @@ irc_handle_isupport_statusmsg (struct server *s, char *value)
 	cstr_set (&s->irc_statusmsg, xstrdup (value));
 }
 
+static void
+irc_handle_isupport_extban (struct server *s, char *value)
+{
+	s->irc_extban_prefix = 0;
+	if (*value && *value != ',')
+		s->irc_extban_prefix = *value++;
+
+	cstr_set (&s->irc_extban_types, xstrdup (*value == ',' ? ++value : ""));
+}
+
 static void
 irc_handle_isupport_chanmodes (struct server *s, char *value)
 {
@@ -7982,6 +8014,7 @@ dispatch_isupport (struct server *s, const char *name, char *value)
 	MATCH ("CHANTYPES",   irc_handle_isupport_chantypes);
 	MATCH ("IDCHAN",      irc_handle_isupport_idchan);
 	MATCH ("STATUSMSG",   irc_handle_isupport_statusmsg);
+	MATCH ("EXTBAN",      irc_handle_isupport_extban);
 	MATCH ("CHANMODES",   irc_handle_isupport_chanmodes);
 	MATCH ("MODES",       irc_handle_isupport_modes);
 
@@ -11646,10 +11679,7 @@ mass_channel_mode_mask_list
 	for (size_t i = 0; i < v.len; i++)
 	{
 		char *target = v.vector[i];
-		// TODO: support EXTBAN=<[PREFIX],TYPES> and leave those alone, too.
-		//   The type may be prefixed by ~, and must be followed by \0 or ':'.
-		//   Make a function like irc_is_extban().
-		if (strpbrk (target, "!@*?"))
+		if (strpbrk (target, "!@*?") || irc_is_extban (a->s, target))
 			continue;
 
 		v.vector[i] = xstrdup_printf ("%s!*@*", target);