diff --git a/isisd/isis_pdu.c b/isisd/isis_pdu.c
index 4311a90..a2ab064 100644
--- a/isisd/isis_pdu.c
+++ b/isisd/isis_pdu.c
@@ -64,7 +64,7 @@
 #endif /* PNBBY */
 
 /* Utility mask array. */
-static u_char maskbit[] = {
+static const u_char maskbit[] = {
   0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff
 };
 
diff --git a/lib/command.c b/lib/command.c
index 31c067a..478125f 100644
--- a/lib/command.c
+++ b/lib/command.c
@@ -82,14 +82,14 @@
 };
 
 /* Default motd string. */
-const char *default_motd =
+static const char *default_motd =
 "\r\n\
 Hello, this is " QUAGGA_PROGNAME " (version " QUAGGA_VERSION ").\r\n\
 " QUAGGA_COPYRIGHT "\r\n\
 \r\n";
 
 
-static struct facility_map {
+static const struct facility_map {
   int facility;
   const char *name;
   size_t match;
@@ -122,7 +122,7 @@
 static const char *
 facility_name(int facility)
 {
-  struct facility_map *fm;
+  const struct facility_map *fm;
 
   for (fm = syslog_facilities; fm->name; fm++)
     if (fm->facility == facility)
@@ -133,7 +133,7 @@
 static int
 facility_match(const char *str)
 {
-  struct facility_map *fm;
+  const struct facility_map *fm;
 
   for (fm = syslog_facilities; fm->name; fm++)
     if (!strncmp(str,fm->name,fm->match))
@@ -506,7 +506,7 @@
   cmd->cmdsize = cmd_cmdsize (cmd->strvec);
 }
 
-static unsigned char itoa64[] =	
+static const unsigned char itoa64[] =
 "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 
 static void
diff --git a/lib/prefix.c b/lib/prefix.c
index 2afaa09..c85e659 100644
--- a/lib/prefix.c
+++ b/lib/prefix.c
@@ -29,7 +29,7 @@
 #include "log.h"
 
 /* Maskbit. */
-static u_char maskbit[] = {0x00, 0x80, 0xc0, 0xe0, 0xf0,
+static const u_char maskbit[] = {0x00, 0x80, 0xc0, 0xe0, 0xf0,
 			         0xf8, 0xfc, 0xfe, 0xff};
 
 /* Number of bits in prefix type. */