diff --git a/lib/nvt_socket.c b/lib/nvt_socket.c
index 2ab2e32..08b1b44 100644
--- a/lib/nvt_socket.c
+++ b/lib/nvt_socket.c
@@ -7,6 +7,7 @@
 #include <string.h>
 #include <unistd.h>
 #include <sys/socket.h>
+#include <sys/un.h>
 
 #include "nvt_log.h"
 #include "nvt_socket.h"
@@ -18,42 +19,95 @@ typedef struct {
     union {
         struct sockaddr gen;
         struct sockaddr_in ipv4;
+        struct sockaddr_in6 ipv6;
+        struct sockaddr_un un;
     };
 } sa_t;
 
 
-static int _sa_host_lookup(sa_t * sa, const char *host)
+static int _sa_host_lookup(sa_t * sa, const char *host, const char *port)
 {
-    struct hostent *server;
+    struct addrinfo hint, *adrinf = NULL, *p;
+    int ret = -1;
 
-    server = gethostbyname(host);
-    if (server == NULL)
-    {
+    memset(&hint, 0, sizeof(struct addrinfo));
+
+    if(getaddrinfo(host, port, &hint, &adrinf) != 0) {
         nvt_log(LOG_ERR, "Cannot resolve host name: %m\n");
         return -1;
     }
 
-    sa->slen = sizeof(sa->ipv4);
-
-    sa->ipv4.sin_family = AF_INET;
-    memcpy(&sa->ipv4.sin_addr.s_addr, server->h_addr, server->h_length);
-
-    return 0;
+    // Priority is given to the use of IPv4
+    // This code must be modified if the preffered protocol is changed or varied.
+    for(p = adrinf; p; p = p->ai_next) {
+        if(p->ai_family == AF_INET) {
+            sa->slen = sizeof(sa->ipv4);
+            memcpy(&sa->ipv4, p->ai_addr, sizeof(struct sockaddr_in));
+            ret = 0;
+            goto exit_host_lookup;
+        }
+    }
+    for(p = adrinf; p; p = p->ai_next) {
+        if(p->ai_family == AF_INET6) {
+            sa->slen = sizeof(sa->ipv6);
+            memcpy(&sa->ipv6, p->ai_addr, sizeof(struct sockaddr_in6));
+            ret = 0;
+            goto exit_host_lookup;
+        }
+    }
+exit_host_lookup:
+    freeaddrinfo(adrinf);
+    return ret;
 }
 
 static int _sa_addr_parse(sa_t * sa, const char *addr)
 {
-    char            host[64], port[64];
+    ssize_t host_len;
+    char host[64];
+    const char *port;
 
     memset(sa, 0, sizeof(sa_t));
 
-    sscanf(addr, "%63[^:]:%63s", host, port);
+    if (strncmp(addr, "unix:", 5) == 0) { // case of unix domain sockets ...
+        addr += 5; // skip "unix:" prefix
+        if(strlen(addr) > sizeof(sa->un.sun_path) - 1) {
+            nvt_log(LOG_ERR, "UNIX domain socket path is too long.\n");
+            return -1;
+        }
+        sa->slen = sizeof(sa->un);
+        sa->un.sun_family = AF_UNIX;
+        strcpy(sa->un.sun_path, addr);
+        sa->type = SOCK_STREAM;
+        return 0;
+    }
 
-    if (_sa_host_lookup(sa, host) != 0)
+    if(!(port = strrchr(addr, ':'))) {
+        nvt_log(LOG_ERR, "bad server address format.\n");
+        return -1;
+    }
+    host_len = (port++) - addr;
+    // *port indicates the last ':', its next is 1st char of the port number
+    if(host_len >= 2 && addr[0] == '[' && addr[host_len-1] == ']') {
+        // IPv6 addresses are enclosed in pair of square brackets.
+        addr += 1;
+        host_len -= 2;
+    } else {
+        if(strchr(addr, ':') != port-1) {
+            nvt_log(LOG_ERR, "addresses containing colons must be enclosed in square brackets.\n");
+            return -1;
+        }
+    }
+    if((ssize_t)sizeof(host) <= host_len) {
+        nvt_log(LOG_ERR, "host name is too long.\n");
+        return -1;
+    }
+    strncpy(host, addr, host_len);
+    host[host_len] = '\0'; // strncpy doesn't add null char
+
+    if (_sa_host_lookup(sa, host, port) != 0)
         return -1;
 
     sa->type = SOCK_STREAM;
-    sa->ipv4.sin_port = htons(atoi(port));
 
     return 0;
 }
@@ -103,7 +157,7 @@ int socket_create_server(const char *addr)
         return -1;
     }
 
-    if (sa.gen.sa_family == AF_INET)
+    if (sa.gen.sa_family == AF_INET || sa.gen.sa_family == AF_INET6)
     {
         /* Avoid TIME_WAIT state on socket close */
         opt = 1;
diff --git a/src/ttynvt.c b/src/ttynvt.c
index c164a22..919f24c 100644
--- a/src/ttynvt.c
+++ b/src/ttynvt.c
@@ -1172,7 +1172,9 @@ static void print_help(void)
             "\t-q\t\tBe quiet (suppress informational messages)\n"
             "\t-r\t\tDisable telnet processing\n"
             "\t-s delay \t\tDelay at close in ms (use u suffix for us)\n"
-            "\t-S server, --server=host:port\n");
+            "\t-S server, --server=host:port\n"
+            "\t\t\t[ipv6addr]:port (connect via IPv6)\n"
+            "\t\t\tunix:/path/to.socket (connect via UNIX domain socket)\n");
 }
 
 static int