diff --git a/exercises/ex04/trout/util.h b/exercises/ex04/trout/util.h
new file mode 100644
index 00000000..b04ff27b
--- /dev/null
+++ b/exercises/ex04/trout/util.h
@@ -0,0 +1,48 @@
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <time.h>
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+#include <netinet/ip_icmp.h>
+#include <netinet/udp.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include <sys/un.h>
+#include <stdarg.h>
+#include <syslog.h>
+#include <unistd.h>
+
+#define MAXLINE 4096
+
+/* the following are a few definitions from Stevens' unp.h */
+typedef	void Sigfunc(int);        /* for signal handlers */
+
+void err_sys (char *fmt, ...);
+void err_quit (char *fmt, ...);
+char *Sock_ntop_host(const struct sockaddr *sa, socklen_t salen);
+int sock_cmp_addr(const struct sockaddr *sa1,
+		  const struct sockaddr *sa2, socklen_t salen);
+void sock_set_port(struct sockaddr *sa, socklen_t salen, int port);
+void tv_sub (struct timeval *out, struct timeval *in);
+char *icmpcode_v4(int code);
+Sigfunc *Signal(int signo, Sigfunc *func);
+void *Calloc(size_t n, size_t size);
+void Gettimeofday(struct timeval *tv, void *foo);
+void Pipe(int *fds);
+void Bind(int fd, const struct sockaddr *sa, socklen_t salen);
+void Setsockopt(int fd, int level, int optname, const void *optval,
+		socklen_t optlen);
+struct addrinfo *Host_serv(const char *host, const char *serv,
+			   int family, int socktype);
+ssize_t Read(int fd, void *ptr, size_t nbytes);
+void Write(int fd, void *ptr, size_t nbytes);
+ssize_t Recvfrom(int fd, void *ptr, size_t nbytes, int flags,
+		 struct sockaddr *sa, socklen_t *salenptr);