--- a/src/nemesis.h
+++ b/src/nemesis.h
@@ -164,10 +164,10 @@
 extern int         verbose;
 extern int         interval;
 extern int         count;
-int                got_link;
-int                got_payload;
-int                got_ipoptions;
-int                got_tcpoptions;
+extern int                got_link;
+extern int                got_payload;
+extern int                got_ipoptions;
+extern int                got_tcpoptions;
 
 struct file {
 	uint8_t *file_buf; /* pointer to file memory */
--- a/src/nemesis.c
+++ b/src/nemesis.c
@@ -10,6 +10,9 @@
 #include <string.h>
 #include <unistd.h>
 
+int got_payload;
+int mode;
+
 extern int optind;
 
 static int usage(char *arg)
--- a/src/nemesis-icmp.c
+++ b/src/nemesis-icmp.c
@@ -12,6 +12,8 @@
 #include <pcap.h>
 #endif
 
+int got_origoptions;
+
 static ETHERhdr etherhdr;
 static IPhdr    iphdr;
 static IPhdr    ipunreach;
--- a/src/nemesis-icmp.h
+++ b/src/nemesis-icmp.h
@@ -39,8 +39,8 @@
 #include "nemesis.h"
 #include <libnet.h>
 
-int mode; /* ICMP injection mode */
-int got_origoptions;
+extern int mode; /* ICMP injection mode */
+extern int got_origoptions;
 
 int buildicmp(ETHERhdr *, IPhdr *, ICMPhdr *, IPhdr *, struct file *, struct file *, struct file *, libnet_t *);
 
--- a/src/nemesis-ospf.h
+++ b/src/nemesis-ospf.h
@@ -43,7 +43,7 @@
 extern NETLSAhdr    netlsahdr;
 extern SUMLSAhdr    sumlsahdr;
 
-int mode; /* OSPF injection mode */
+extern int mode; /* OSPF injection mode */
 
 int buildospf(ETHERhdr *, IPhdr *, struct file *, struct file *, libnet_t *, int);
 
--- a/src/nemesis-dns.c
+++ b/src/nemesis-dns.c
@@ -12,6 +12,8 @@
 #include <pcap.h>
 #endif
 
+int state;
+
 static ETHERhdr etherhdr;
 static IPhdr    iphdr;
 static TCPhdr   tcphdr;
--- a/src/nemesis-dns.h
+++ b/src/nemesis-dns.h
@@ -29,7 +29,7 @@
 #include "nemesis.h"
 #include <libnet.h>
 
-int state; /* default to UDP */
+extern int state; /* default to UDP */
 
 int builddns(ETHERhdr *, IPhdr *, TCPhdr *, UDPhdr *, DNShdr *, struct file *, struct file *, struct file *, libnet_t *);