diff --git a/src/dhcpd-pools.h b/src/dhcpd-pools.h
index 7c32ecb..4d785fe 100644
--- a/src/dhcpd-pools.h
+++ b/src/dhcpd-pools.h
@@ -162,6 +162,7 @@ void *safe_malloc(const size_t size)
     ;
 void *safe_realloc(void *ptr, const size_t size);
 char *safe_strdup(const char *str) __attribute__ ((nonnull(1)));
+int xstrstr(char *a, char *b, int len);
 void print_version(void) __attribute__ ((noreturn));
 void usage(int status) __attribute__ ((noreturn));
 /* qsort required functions... */
diff --git a/src/getdata.c b/src/getdata.c
index bce5ce4..8a0786d 100644
--- a/src/getdata.c
+++ b/src/getdata.c
@@ -134,14 +134,14 @@ int parse_leases(void)
 			    config.dhcpdlease_file);
 		}
 		/* It's a lease, save IP */
-		if (strstr(line, "lease") == line) {
+		if (xstrstr(line, "lease", 5)) {
 			strncpy(ipstring, line, MAXLEN);
 			nth_field(2, ipstring, ipstring);
 			inet_aton(ipstring, &inp);
 			sw_active_lease = 0;
 		}
 		/* Copy IP to correct array */
-		else if (strstr(line, "binding state active")) {
+		else if (xstrstr(line, "  binding state active", 22)) {
 			leases[num_leases] = htonl(inp.s_addr);
 			num_leases++;
 			if (leasesmallocsize < num_leases) {
@@ -151,7 +151,7 @@ int parse_leases(void)
 				leasesmallocsize /= sizeof(uint32_t);
 			}
 			sw_active_lease = 1;
-		} else if (strstr(line, "  binding state free")) {
+		} else if (xstrstr(line, "  binding state free", 20)) {
 			touches[num_touches] = htonl(inp.s_addr);
 			num_touches++;
 			if (touchesmallocsize < num_touches) {
@@ -161,7 +161,7 @@ int parse_leases(void)
 				    safe_realloc(touches, touchesmallocsize);
 				touchesmallocsize /= sizeof(uint32_t);
 			}
-		} else if (strstr(line, "  binding state backup")) {
+		} else if (xstrstr(line, "  binding state backup", 22)) {
 			if (num_backups == 0) {
 				backups =
 				    safe_malloc(sizeof(uint32_t) *
@@ -180,7 +180,7 @@ int parse_leases(void)
 
 		if ((macaddr != NULL)
 		    && (sw_active_lease == 1)
-		    && (strstr(line, "hardware ethernet"))) {
+		    && (xstrstr(line, "  hardware ethernet", 19))) {
 			nth_field(3, macstring, line);
 			macstring[17] = '\0';
 			macaddr_p->ethernet = safe_strdup(macstring);
diff --git a/src/other.c b/src/other.c
index c18f3ac..f489775 100644
--- a/src/other.c
+++ b/src/other.c
@@ -78,6 +78,32 @@ void *safe_realloc(void *ptr, const size_t size)
 	return ret;
 }
 
+int
+#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
+    __attribute__ ((hot))
+#endif
+    xstrstr(char *a, char *b, int len)
+{
+	int i;
+	/* two spaces are very common in lease file, after them
+	 * nearly everything differs */
+	if (a[2] != b[2]) {
+	  return false;
+	}
+	/* "  binding state " == 16 chars, this will skip right
+         * to first difering line. */
+	if (17 < len && a[17] != b[17]) {
+	  return false;
+	}
+	/* looking good, double check the whole thing... */
+	for (i = 0; a[i] != '\0' && b[i] != '\0'; i++) {
+		if (a[i] != b[i]) {
+			return false;
+		}
+	}
+	return true;
+}
+
 /* Simple strdup wrapper */
 char *safe_strdup(const char *str)
 {