diff --git a/classes.py b/classes.py
index d619508..66bb63d 100644
--- a/classes.py
+++ b/classes.py
@@ -876,12 +876,11 @@ class Irc():
 
     def isInternalClient(self, numeric):
         """
-        Checks whether the given numeric is a PyLink Client,
-        returning the SID of the server it's on if so.
+        Returns whether the given client numeric (UID) is a PyLink client.
         """
-        for sid in self.servers:
-            if self.servers[sid].internal and numeric in self.servers[sid].users:
-                return sid
+        sid = self.getServer(numeric)
+        if sid and self.servers[sid].internal:
+            return True
         return False
 
     def isInternalServer(self, sid):
diff --git a/protocols/inspircd.py b/protocols/inspircd.py
index c09f8da..e1568b0 100644
--- a/protocols/inspircd.py
+++ b/protocols/inspircd.py
@@ -71,10 +71,12 @@ class InspIRCdProtocol(TS6BaseProtocol):
         # so what we're actually doing here is sending FJOIN from the server,
         # on behalf of the clients that are joining.
         channel = self.irc.toLower(channel)
-        server = self.irc.isInternalClient(client)
-        if not server:
+
+        server = self.irc.getServer(client)
+        if not self.irc.isInternalServer(server):
             log.error('(%s) Error trying to join %r to %r (no such client exists)', self.irc.name, client, channel)
             raise LookupError('No such PyLink client exists.')
+
         # Strip out list-modes, they shouldn't be ever sent in FJOIN.
         modes = [m for m in self.irc.channels[channel].modes if m[0] not in self.irc.cmodes['*A']]
         self._send(server, "FJOIN {channel} {ts} {modes} :,{uid}".format(