diff --git a/test/libc/dns/servicestxt_test.c b/test/libc/dns/servicestxt_test.c
new file mode 100644
index 000000000..2f1875de1
--- /dev/null
+++ b/test/libc/dns/servicestxt_test.c
@@ -0,0 +1,135 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ This is free and unencumbered software released into the public domain.      │
+│                                                                              │
+│ Anyone is free to copy, modify, publish, use, compile, sell, or              │
+│ distribute this software, either in source code form or as a compiled        │
+│ binary, for any purpose, commercial or non-commercial, and by any            │
+│ means.                                                                       │
+│                                                                              │
+│ In jurisdictions that recognize copyright laws, the author or authors        │
+│ of this software dedicate any and all copyright interest in the              │
+│ software to the public domain. We make this dedication for the benefit       │
+│ of the public at large and to the detriment of our heirs and                 │
+│ successors. We intend this dedication to be an overt act of                  │
+│ relinquishment in perpetuity of all present and future rights to this        │
+│ software under copyright law.                                                │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,              │
+│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF           │
+│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.       │
+│ IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR            │
+│ OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,        │
+│ ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR        │
+│ OTHER DEALINGS IN THE SOFTWARE.                                              │
+│                                                                              │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/dns/servicestxt.h"
+
+#include "libc/dns/dns.h"
+#include "libc/dns/ent.h"
+#include "libc/calls/calls.h"
+#include "libc/testlib/testlib.h"
+
+char testlib_enable_tmp_setup_teardown;
+
+void SetUp() {
+  int fd;
+  const char* sample = "\
+# skip comment string\n\
+chargen		19/tcp		ttytst source\n\
+chargen		19/udp		ttytst source\n\
+ssh		    22/tcp		# SSH Remote Login Protocol";
+
+  ASSERT_NE(-1, (fd = creat("services", 0755)));
+  ASSERT_NE(-1, write(fd, sample, strlen(sample)));
+  ASSERT_NE(-1, close(fd));
+}
+
+TEST(LookupServicesByPort, GetNameWhenPortCorrect) {
+  char name[16]; /* sample has only names of length 3 */
+  char proto1[] = "tcp";
+  char proto2[] = "udp";
+  char* localproto[1];
+
+  localproto[0] = NULL;
+  ASSERT_EQ(
+      -1, /* non existent port */
+      LookupServicesByPort(965, localproto, name, sizeof(name), "services"));
+  ASSERT_EQ(NULL, localproto[0]);
+
+  ASSERT_EQ(
+      -1, /* port not in network byte order */
+      LookupServicesByPort(22, localproto, name, sizeof(name), "services"));
+  ASSERT_EQ(NULL, localproto[0]);
+
+  localproto[0] = proto2;
+  ASSERT_EQ(-1, /* port ok but wrong protocol */
+            LookupServicesByPort(htons(22), localproto, name, sizeof(name),
+                                 "services"));
+  ASSERT_EQ(localproto[0], proto2);
+
+  localproto[0] = proto1;
+  ASSERT_EQ(0, LookupServicesByPort(htons(22), localproto, name, sizeof(name),
+                                    "services"));
+  ASSERT_STREQ(name, "ssh");
+  ASSERT_EQ(localproto[0], proto1);
+
+  localproto[0] = proto2;
+  ASSERT_EQ(0, LookupServicesByPort(htons(19), localproto, name,
+                                    sizeof(name), "services"));
+  ASSERT_STREQ(name, "chargen");
+  ASSERT_EQ(localproto[0], proto2);
+
+  localproto[0] = NULL;
+  ASSERT_EQ(0, /* pick first matching protocol */
+            LookupServicesByPort(htons(19), localproto, name, sizeof(name),
+                                 "services"));
+  ASSERT_STREQ(name, "chargen");
+  ASSERT_NE(NULL, localproto[0]); /* got alloc'd during the call */
+  ASSERT_STREQ(localproto[0], "tcp");
+  free(localproto[0]);
+}
+
+TEST(LookupServicesByName, GetPortWhenNameOrAlias) {
+  char name[16]; /* sample has only names of length 3 */
+  char proto1[] = "tcp";
+  char proto2[] = "udp";
+  char* localproto[1];
+
+  localproto[0] = NULL;
+  ASSERT_EQ(
+      -1, /* non-existent name */
+      LookupServicesByName("http", localproto, name, sizeof(name), "services"));
+  ASSERT_EQ(NULL, localproto[0]);
+
+  localproto[0] = proto2;
+  ASSERT_EQ(
+      -1, /* name exists but wrong protocol */
+      LookupServicesByName("ssh", localproto, name, sizeof(name), "services"));
+  ASSERT_EQ(localproto[0], proto2);
+
+  localproto[0] = proto1;
+  ASSERT_EQ(
+      htons(22), /* in network byte order */
+      LookupServicesByName("ssh", localproto, name, sizeof(name), "services"));
+  ASSERT_STREQ(name, "ssh"); /* official name written to buffer */
+  ASSERT_EQ(localproto[0], proto1);
+
+  localproto[0] = proto2;
+  ASSERT_EQ(htons(19), /* works if alias provided */
+            LookupServicesByName("ttytst", localproto, name, sizeof(name),
+                                 "services"));
+  ASSERT_STREQ(name, "chargen"); /* official name written to buffer */
+  ASSERT_EQ(localproto[0], proto2);
+
+  localproto[0] = NULL;
+  ASSERT_EQ(htons(19), /* pick first matching protocol */
+            LookupServicesByName("source", localproto, name, sizeof(name),
+                                 "services"));
+  ASSERT_STREQ(name, "chargen");
+  ASSERT_NE(NULL, localproto[0]); /* got alloc'd during the call */
+  ASSERT_STREQ(localproto[0], "tcp");
+  free(localproto[0]);
+}
diff --git a/test/libc/dns/test.mk b/test/libc/dns/test.mk
index 0690fd106..4fe280243 100644
--- a/test/libc/dns/test.mk
+++ b/test/libc/dns/test.mk
@@ -23,6 +23,7 @@ TEST_LIBC_DNS_CHECKS =					\
 	$(TEST_LIBC_DNS_SRCS_TEST:%.c=o/$(MODE)/%.com.runs)
 
 TEST_LIBC_DNS_DIRECTDEPS =				\
+	LIBC_CALLS					\
 	LIBC_DNS					\
 	LIBC_FMT					\
 	LIBC_INTRIN					\