diff --git a/sys/posix/Makefile b/sys/posix/Makefile
index 095298af20..bd15ac0af2 100644
--- a/sys/posix/Makefile
+++ b/sys/posix/Makefile
@@ -1,4 +1,4 @@
-INCLUDES = -I../include -I$(RIOTBASE)/core/include
+INCLUDES = -I$(RIOTBASE)/sys/include -I$(RIOTBASE)/core/include -Iinclude
 MODULE =posix
 
 include $(RIOTBASE)/Makefile.base
diff --git a/sys/posix/doc.txt b/sys/posix/doc.txt
new file mode 100644
index 0000000000..95aef02e23
--- /dev/null
+++ b/sys/posix/doc.txt
@@ -0,0 +1,16 @@
+/*
+ * Copyright (C) 2013  INRIA.
+ *
+ * This file subject to the terms and conditions of the GNU Lesser General
+ * Public License. See the file LICENSE in the top level directory for more
+ * details.
+ */
+
+/**
+ * @defgroup posix  POSIX wrapper of RIOT
+ * @brief   POSIX header files
+ * @see <a href="http://pubs.opengroup.org/onlinepubs/9699919799/">
+ *          The Open Group Specifications Issue 7
+ *      </a>
+ * @ingroup posix
+ */
diff --git a/sys/posix/include/strings.h b/sys/posix/include/strings.h
new file mode 100644
index 0000000000..f1262aa554
--- /dev/null
+++ b/sys/posix/include/strings.h
@@ -0,0 +1,120 @@
+/**
+ * Copyright (C) 2013  INRIA.
+ *
+ * This file subject to the terms and conditions of the GNU Lesser General
+ * Public License. See the file LICENSE in the top level directory for more
+ * details.
+ */
+
+/**
+ * @addtogroup posix
+ * @{
+ */
+
+/**
+ * @file    strings.h
+ * @brief   string operations
+ *
+ * @see     <a href="http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/strings.h.html">
+ *              The Open Group Base Specifications Issue 7, <strings.h>
+ *          </a>
+ *
+ * @author  Freie Universität Berlin
+ * @author  Martin Lenders <mlenders@inf.fu-berlin.de>
+ */
+#ifndef STRINGS_H
+#define STRINGS_H
+
+#include <sys/types.h>
+
+/**
+ * @brief   Returns the position of the first (least significant) bit set in
+ *          integer *i*, or 0 if no bits are set in i.
+ *
+ * @param[in] i    an integer number.
+ *
+ * @return  Position (1 for least significant bit) of the first bit set,
+ *          0 if no bits are set.
+ *
+ * @see <a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/ffs.html">
+ *          The Open Group Base Specification Issue 7, ffs
+ *      </a>
+ */
+#define ffs(i) __builtin_ffs(i)
+
+/**
+ * @brief   Compares two strings *s1* and *s2*, ignoring the case of the
+ *          characters for not more than n bytes from the strings.
+ *
+ * @param[in] s1    a string.
+ * @param[in] s2    another string.
+ * @param[in] n     number of bytes to be compared
+ *
+ * @return  A value greater 0 if, ignoring the case of the character, *s1* is
+ *          greater than *s2* up to n bytes, less than 0 if smaller, and 0 if
+ *          equal
+ *
+ * @see <a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/strcasecmp.html">
+ *          The Open Group Base Specification Issue 7, strcasecmp
+ *      </a>
+ */
+int strncasecmp(const char *s1, const char *s2, size_t n);
+
+/**
+ * @brief   Compares two strings *s1* and *s2*, ignoring the case of the
+ *          characters for not more than n bytes from the strings, but using
+ *          the current locale settings to determine the case.
+ *
+ * @note    Since RIOT does not support locales (yet), this is just an
+ *          alias for strncasecmp()
+ *
+ * @param[in] s1    a string.
+ * @param[in] s2    another string.
+ * @param[in] n     number of bytes to be compared
+ *
+ * @return  A value greater 0 if, ignoring the case of the character, *s1* is
+ *          greater than *s2* up to n bytes, less than 0 if smaller, and 0 if
+ *          equal
+ *
+ * @see <a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/strcasecmp.html">
+ *          The Open Group Base Specification Issue 7, strcasecmp
+ *      </a>
+ */
+#define strncasecmp_l(s1, s2, n, l) (strncasecmp(s1, s2, n))
+
+/**
+ * @brief   Compares two strings *s1* and *s2*, ignoring the case of the characters.
+ *
+ * @param[in] s1    a string.
+ * @param[in] s2    another string.
+ *
+ * @return  A value greater 0 if, ignoring the case of the character, *s1* is
+ *          greater than *s2*, less than 0 if smaller, and 0 if equal
+ *
+ * @see <a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/strcasecmp.html">
+ *          The Open Group Base Specification Issue 7, strcasecmp
+ *      </a>
+ */
+#define strcasecmp(s1, s2) strncasecmp(s1, s2, -1)
+
+/**
+ * @brief   Compares two strings *s1* and *s2*, ignoring the case of the
+ *          characters, but using the current locale settings to determine the
+ *          case.
+ *
+ * @note    Since RIOT does not support locales (yet), this is just an
+ *          alias for strcasecmp()
+ *
+ * @param[in] s1    a string.
+ * @param[in] s2    another string.
+ *
+ * @return  A value greater 0 if, ignoring the case of the character, *s1* is
+ *          greater than *s2*, less than 0 if smaller, and 0 if equal
+ *
+ * @see <a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/strcasecmp.html">
+ *          The Open Group Base Specification Issue 7, strcasecmp
+ *      </a>
+ */
+#define strcasecmp_l(s1, s2, l) strncasecmp(s1, s2, -1)
+
+#endif /* STRINGS_H */
diff --git a/sys/posix/strings.c b/sys/posix/strings.c
new file mode 100644
index 0000000000..2ef5867919
--- /dev/null
+++ b/sys/posix/strings.c
@@ -0,0 +1,16 @@
+#include <strings.h>
+#include <ctype.h>
+
+int strncasecmp(const char *s1, const char *s2, size_t n)
+{
+    while (n-- && tolower(*s1) == tolower(*s2)) {
+        if (!n && !*s1) {
+            break;
+        }
+
+        s1++;
+        s2++;
+    }
+
+    return (tolower(*s1) - tolower(*s2));
+}