diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
index 90fba7484e3..07c2340702c 100644
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -576,14 +576,18 @@ findpcb:
 	if (inp == NULL) {
 		if (log_in_vain) {
 #ifdef INET6
-			char dbuf[INET6_ADDRSTRLEN], sbuf[INET6_ADDRSTRLEN];
+			char dbuf[INET6_ADDRSTRLEN+2], sbuf[INET6_ADDRSTRLEN+2];
 #else
 			char dbuf[4*sizeof "123"], sbuf[4*sizeof "123"];
 #endif
 
 			if (isipv6) {
-				strcpy(dbuf, ip6_sprintf(&ip6->ip6_dst));
-				strcpy(sbuf, ip6_sprintf(&ip6->ip6_src));
+				strcpy(dbuf, "[");
+				strcpy(sbuf, "[");
+				strcat(dbuf, ip6_sprintf(&ip6->ip6_dst));
+				strcat(sbuf, ip6_sprintf(&ip6->ip6_src));
+				strcat(dbuf, "]");
+				strcat(sbuf, "]");
 			} else {
 				strcpy(dbuf, inet_ntoa(ip->ip_dst));
 				strcpy(sbuf, inet_ntoa(ip->ip_src));
diff --git a/sys/netinet/tcp_reass.c b/sys/netinet/tcp_reass.c
index 90fba7484e3..07c2340702c 100644
--- a/sys/netinet/tcp_reass.c
+++ b/sys/netinet/tcp_reass.c
@@ -576,14 +576,18 @@ findpcb:
 	if (inp == NULL) {
 		if (log_in_vain) {
 #ifdef INET6
-			char dbuf[INET6_ADDRSTRLEN], sbuf[INET6_ADDRSTRLEN];
+			char dbuf[INET6_ADDRSTRLEN+2], sbuf[INET6_ADDRSTRLEN+2];
 #else
 			char dbuf[4*sizeof "123"], sbuf[4*sizeof "123"];
 #endif
 
 			if (isipv6) {
-				strcpy(dbuf, ip6_sprintf(&ip6->ip6_dst));
-				strcpy(sbuf, ip6_sprintf(&ip6->ip6_src));
+				strcpy(dbuf, "[");
+				strcpy(sbuf, "[");
+				strcat(dbuf, ip6_sprintf(&ip6->ip6_dst));
+				strcat(sbuf, ip6_sprintf(&ip6->ip6_src));
+				strcat(dbuf, "]");
+				strcat(sbuf, "]");
 			} else {
 				strcpy(dbuf, inet_ntoa(ip->ip_dst));
 				strcpy(sbuf, inet_ntoa(ip->ip_src));
diff --git a/sys/netinet6/udp6_usrreq.c b/sys/netinet6/udp6_usrreq.c
index c9fcbcb32a6..a7e46b9a268 100644
--- a/sys/netinet6/udp6_usrreq.c
+++ b/sys/netinet6/udp6_usrreq.c
@@ -346,7 +346,7 @@ udp6_input(mp, offp, proto)
 
 			strcpy(buf, ip6_sprintf(&ip6->ip6_dst));
 			log(LOG_INFO,
-			    "Connection attempt to UDP %s:%d from %s:%d\n",
+			    "Connection attempt to UDP [%s]:%d from [%s]:%d\n",
 			    buf, ntohs(uh->uh_dport),
 			    ip6_sprintf(&ip6->ip6_src), ntohs(uh->uh_sport));
 		}