diff --git a/server/conf.c b/server/conf.c
index e6046ed7c9..6243c936ef 100644
--- a/server/conf.c
+++ b/server/conf.c
@@ -116,44 +116,40 @@ static void ups_update(const char *fn, const char *name, const char *desc)
 /* return 1 if usable, 0 if not */
 static int parse_upsd_conf_args(int numargs, char **arg)
 {
+	unsigned int	temp;
+
 	/* everything below here uses up through arg[1] */
 	if (numargs < 2)
 		return 0;
 
 	/* MAXAGE <seconds> */
 	if (!strcmp(arg[0], "MAXAGE")) {
-		if (isdigit(arg[1])) {
-			maxage = atoi(arg[1]);
+		if (str_to_uint(arg[1], &temp, 10)) {
+			maxage = temp;
 			return 1;
 		}
-		else {
-			upslogx(LOG_ERR, "MAXAGE has non numeric value (%s)!", arg[1]);
-			return 0;
-		}
+		upslogx(LOG_ERR, "Could not convert %s (%s) to an unsigned int (%s)!", arg[0], arg[1], strerror(errno));
+		return 0;
 	}
 
 	/* TRACKINGDELAY <seconds> */
 	if (!strcmp(arg[0], "TRACKINGDELAY")) {
-		if (isdigit(arg[1])) {
-			tracking_delay = atoi(arg[1]);
+		if (str_to_uint(arg[1], &temp, 10)) {
+			tracking_delay = temp;
 			return 1;
 		}
-		else {
-			upslogx(LOG_ERR, "TRACKINGDELAY has non numeric value (%s)!", arg[1]);
-			return 0;
-		}
+		upslogx(LOG_ERR, "Could not convert %s (%s) to an unsigned int (%s)!", arg[0], arg[1], strerror(errno));
+		return 0;
 	}
 
 	/* MAXCONN <connections> */
 	if (!strcmp(arg[0], "MAXCONN")) {
-		if (isdigit(arg[1])) {
-			maxconn = atoi(arg[1]);
+		if (str_to_uint(arg[1], &temp, 10)) {
+			maxconn = temp;
 			return 1;
 		}
-		else {
-			upslogx(LOG_ERR, "MAXCONN has non numeric value (%s)!", arg[1]);
-			return 0;
-		}
+		upslogx(LOG_ERR, "Could not convert %s (%s) to an unsigned int (%s)!", arg[0], arg[1], strerror(errno));
+		return 0;
 	}
 
 	/* STATEPATH <dir> */
@@ -187,14 +183,12 @@ static int parse_upsd_conf_args(int numargs, char **arg)
 #ifdef WITH_CLIENT_CERTIFICATE_VALIDATION
 	/* CERTREQUEST (0 | 1 | 2) */
 	if (!strcmp(arg[0], "CERTREQUEST")) {
-		if (isdigit(arg[1])) {
-			certrequest = atoi(arg[1]);
+		if (str_to_uint(arg[1], &temp, 10)) {
+			certrequest = temp;
 			return 1;
 		}
-		else {
-			upslogx(LOG_ERR, "CERTREQUEST has non numeric value (%s)!", arg[1]);
-			return 0;
-		}
+		upslogx(LOG_ERR, "Could not convert %s (%s) to an unsigned int (%s)!", arg[0], arg[1], strerror(errno));
+		return 0;
 	}
 #endif /* WITH_CLIENT_CERTIFICATE_VALIDATION */
 #endif /* WITH_OPENSSL | WITH_NSS */
diff --git a/server/netssl.c b/server/netssl.c
index c2f409899d..d1c818e261 100644
--- a/server/netssl.c
+++ b/server/netssl.c
@@ -46,7 +46,7 @@ char	*certname = NULL;
 char	*certpasswd = NULL;
 
 #ifdef WITH_CLIENT_CERTIFICATE_VALIDATION
-int certrequest = 0;
+unsigned int certrequest = 0;
 #endif /* WITH_CLIENT_CERTIFICATE_VALIDATION */
 
 static int	ssl_initialized = 0;
diff --git a/server/netssl.h b/server/netssl.h
index 8f68168969..33f73ade0f 100644
--- a/server/netssl.h
+++ b/server/netssl.h
@@ -32,7 +32,7 @@ extern char	*certfile;
 extern char	*certname;
 extern char	*certpasswd;
 #ifdef WITH_CLIENT_CERTIFICATE_VALIDATION
-extern int certrequest;
+extern unsigned int certrequest;
 #endif /* WITH_CLIENT_CERTIFICATE_VALIDATION */
 
 /* List possible values for certrequested */
diff --git a/server/sstate.c b/server/sstate.c
index 0365cd30f6..28910dbf3e 100644
--- a/server/sstate.c
+++ b/server/sstate.c
@@ -341,7 +341,7 @@ const cmdlist_t *sstate_getcmdlist(const upstype_t *ups)
 	return ups->cmdlist;
 }
 
-int sstate_dead(upstype_t *ups, int maxage)
+int sstate_dead(upstype_t *ups, unsigned int maxage)
 {
 	time_t	now;
 	double	elapsed;
diff --git a/server/sstate.h b/server/sstate.h
index fe8485ced3..0b274c108c 100644
--- a/server/sstate.h
+++ b/server/sstate.h
@@ -47,7 +47,7 @@ const cmdlist_t *sstate_getcmdlist(const upstype_t *ups);
 void sstate_makeinfolist(const upstype_t *ups, char *buf, size_t bufsize);
 void sstate_makerwlist(const upstype_t *ups, char *buf, size_t bufsize);
 void sstate_makeinstcmdlist_t(const upstype_t *ups, char *buf, size_t bufsize);
-int sstate_dead(upstype_t *ups, int maxage);
+int sstate_dead(upstype_t *ups, unsigned int maxage);
 void sstate_infofree(upstype_t *ups);
 void sstate_cmdfree(upstype_t *ups);
 int sstate_sendline(upstype_t *ups, const char *buf);
diff --git a/server/upsd.c b/server/upsd.c
index a49b51110f..855a3ce0fe 100644
--- a/server/upsd.c
+++ b/server/upsd.c
@@ -52,13 +52,13 @@ int	deny_severity = LOG_WARNING;
 	upstype_t	*firstups = NULL;
 
 	/* default 15 seconds before data is marked stale */
-	int	maxage = 15;
+	unsigned int	maxage = 15;
 
 	/* default to 1h before cleaning up status tracking entries */
-	int	tracking_delay = 3600;
+	unsigned int	tracking_delay = 3600;
 
 	/* preloaded to {OPEN_MAX} in main, can be overridden via upsd.conf */
-	int	maxconn = 0;
+	unsigned int	maxconn = 0;
 
 	/* preloaded to STATEPATH in main, can be overridden via upsd.conf */
 	char	*statepath = NULL;
@@ -691,7 +691,7 @@ static void upsd_cleanup(void)
 
 void poll_reload(void)
 {
-	int	ret;
+	unsigned int	ret;
 
 	ret = sysconf(_SC_OPEN_MAX);
 
@@ -922,7 +922,8 @@ int nut_uuid_v4(char *uuid_str)
 /* service requests and check on new data */
 static void mainloop(void)
 {
-	int	i, ret, nfds = 0;
+	unsigned int	i, nfds = 0;
+	int				ret;
 
 	upstype_t	*ups;
 	nut_ctype_t		*client, *cnext;
@@ -1246,7 +1247,7 @@ int main(int argc, char **argv)
 		chroot_start(chroot_path);
 	}
 
-	/* default to system limit (may be overridden in upsd.conf */
+	/* default to system limit (may be overridden in upsd.conf) */
 	maxconn = sysconf(_SC_OPEN_MAX);
 
 	/* handle upsd.conf */
diff --git a/server/upsd.h b/server/upsd.h
index 2cd3eb399e..7bff8a5f75 100644
--- a/server/upsd.h
+++ b/server/upsd.h
@@ -91,7 +91,7 @@ int tracking_is_enabled(void);
 
 /* declarations from upsd.c */
 
-extern int		maxage, maxconn, tracking_delay;
+extern unsigned int	maxage, maxconn, tracking_delay;
 extern char		*statepath, *datapath;
 extern upstype_t	*firstups;
 extern nut_ctype_t	*firstclient;