diff --git a/appl/telnet/telnetd/ext.h b/appl/telnet/telnetd/ext.h
index c6e58c17c..7650e27c9 100644
--- a/appl/telnet/telnetd/ext.h
+++ b/appl/telnet/telnetd/ext.h
@@ -116,15 +116,15 @@ void tty_tspeed (int val);
 void tty_rspeed (int val);
 void getptyslave (void);
 int cleanopen (char *line);
-void startslave (char *host, int autologin, char *autoname);
+void startslave (const char *host, const char *, int autologin, char *autoname);
 void init_env (void);
-void start_login (char *host, int autologin, char *name);
+void start_login (const char *host, int autologin, char *name);
 void cleanup (int sig);
 int main (int argc, char **argv);
 int getterminaltype (char *name, size_t);
 void _gettermname (void);
 int terminaltypeok (char *s);
-void my_telnet (int f, int p, char*, int, char*);
+void my_telnet (int f, int p, const char*, const char *, int, char*);
 void interrupt (void);
 void sendbrk (void);
 void sendsusp (void);