diff --git a/src/network/getservbyname_r.c b/src/network/getservbyname_r.c
index ad3d6164c2e1c63089376f8fa53340ca553ef57e..cad6317ab84243e5bc8de3a1d8ce17eb4a688a5e 100644
--- a/src/network/getservbyname_r.c
+++ b/src/network/getservbyname_r.c
@@ -5,6 +5,7 @@
 #include <inttypes.h>
 #include <errno.h>
 #include <string.h>
+#include <stdlib.h>
 #include "lookup.h"
 
 #define ALIGN (sizeof(struct { char a; char *b; }) - sizeof(char *))
@@ -17,6 +18,11 @@ int getservbyname_r(const char *name, const char *prots,
 
 	*res = 0;
 
+	/* Don't treat numeric port number strings as service records. */
+	char *end = "";
+	strtoul(name, &end, 10);
+	if (!*end) return ENOENT;
+
 	/* Align buffer */
 	align = -(uintptr_t)buf & ALIGN-1;
 	if (buflen < 2*sizeof(char *)+align)
diff --git a/src/network/getservbyport_r.c b/src/network/getservbyport_r.c
index 0ae0e41587fe03f36708583edd6596195d0ce25d..b7f21c6b398a52c4eeb61ea9a94f12a1e88e7b71 100644
--- a/src/network/getservbyport_r.c
+++ b/src/network/getservbyport_r.c
@@ -5,6 +5,7 @@
 #include <inttypes.h>
 #include <errno.h>
 #include <string.h>
+#include <stdlib.h>
 
 int getservbyport_r(int port, const char *prots,
 	struct servent *se, char *buf, size_t buflen, struct servent **res)
@@ -51,6 +52,9 @@ int getservbyport_r(int port, const char *prots,
 		break;
 	}
 
+	/* A numeric port string is not a service record. */
+	if (strtol(buf, 0, 10)==ntohs(port)) return ENOENT;
+
 	*res = se;
 	return 0;
 }