diff --git a/CHANGELOG b/CHANGELOG
index 3d07a21b7..137ae8e3f 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,5 +1,8 @@
 #Nmap Changelog ($Id$); -*-text-*-
 
+o New Nmap option --unique will prevent Nmap from scanning the same IP address
+  twice, which can happen when different names resolve to the same address. [Daniel Miller]
+
 o [NSE][GH#2175] Fixed NSE so it will not consolidate all port script output
   for targets which share an IP (e.g. HTTP vhosts) under one target. [Daniel Miller]
 
diff --git a/NmapOps.cc b/NmapOps.cc
index fab4ac3b8..bc2bab7d5 100644
--- a/NmapOps.cc
+++ b/NmapOps.cc
@@ -298,6 +298,7 @@ void NmapOps::Initialize() {
   deprecated_xml_osclass = false;
   always_resolve = false;
   resolve_all = false;
+  unique = false;
   dns_servers = NULL;
   implicitARPPing = true;
   numhosts_scanned = 0;
diff --git a/NmapOps.h b/NmapOps.h
index e3b9f2ba8..29ee2cbaa 100644
--- a/NmapOps.h
+++ b/NmapOps.h
@@ -304,6 +304,7 @@ class NmapOps {
   bool mass_dns;
   bool always_resolve;
   bool resolve_all;
+  bool unique;
   char *dns_servers;
 
   /* Do IPv4 ARP or IPv6 ND scan of directly connected Ethernet hosts, even if
diff --git a/nmap.cc b/nmap.cc
index d844e7886..18604259a 100644
--- a/nmap.cc
+++ b/nmap.cc
@@ -593,6 +593,7 @@ void parse_options(int argc, char **argv) {
     {"version-all", no_argument, 0, 0},
     {"system-dns", no_argument, 0, 0},
     {"resolve-all", no_argument, 0, 0},
+    {"unique", no_argument, 0, 0},
     {"log-errors", no_argument, 0, 0},
     {"deprecated-xml-osclass", no_argument, 0, 0},
     {(char*)k, no_argument, 0, 0},
@@ -844,6 +845,8 @@ void parse_options(int argc, char **argv) {
           o.dns_servers = strdup(optarg);
         } else if (strcmp(long_options[option_index].name, "resolve-all") == 0) {
           o.resolve_all = true;
+        } else if (strcmp(long_options[option_index].name, "unique") == 0) {
+          o.unique = true;
         } else if (strcmp(long_options[option_index].name, "log-errors") == 0) {
           /*Nmap Log errors is deprecated and is now always enabled by default.
           This option is left in so as to not break anybody's scanning scripts.
diff --git a/targets.cc b/targets.cc
index 444e07bc8..7592e22d1 100644
--- a/targets.cc
+++ b/targets.cc
@@ -423,7 +423,7 @@ bail:
   return NULL;
 }
 
-static Target *next_target(HostGroupState *hs, const struct addrset *exclude_group,
+static Target *next_target(HostGroupState *hs, struct addrset *exclude_group,
   struct scan_lists *ports, int pingtype) {
   struct sockaddr_storage ss;
   size_t sslen;
@@ -473,10 +473,14 @@ tryagain:
   if (t == NULL)
     goto tryagain;
 
+  if (o.unique) {
+    // Use the exclude list to avoid scanning this IP again if the user requested it.
+    addrset_add_spec(exclude_group, t->targetipstr(), o.af(), 0);
+  }
   return t;
 }
 
-static void refresh_hostbatch(HostGroupState *hs, const struct addrset *exclude_group,
+static void refresh_hostbatch(HostGroupState *hs, struct addrset *exclude_group,
   struct scan_lists *ports, int pingtype) {
   int i;
   bool arpping_done = false;
@@ -570,7 +574,7 @@ static void refresh_hostbatch(HostGroupState *hs, const struct addrset *exclude_
     nmap_mass_rdns(hs->hostbatch, hs->current_batch_sz);
 }
 
-Target *nexthost(HostGroupState *hs, const struct addrset *exclude_group,
+Target *nexthost(HostGroupState *hs, struct addrset *exclude_group,
                  struct scan_lists *ports, int pingtype) {
   if (hs->next_batch_no >= hs->current_batch_sz)
     refresh_hostbatch(hs, exclude_group, ports, pingtype);
diff --git a/targets.h b/targets.h
index 65bfd0b8b..fedb00806 100644
--- a/targets.h
+++ b/targets.h
@@ -106,7 +106,7 @@ public:
 };
 
 /* ports is used to pass information about what ports to use for host discovery */
-Target *nexthost(HostGroupState *hs,const struct addrset *exclude_group,
+Target *nexthost(HostGroupState *hs, struct addrset *exclude_group,
                  struct scan_lists *ports, int pingtype);
 int load_exclude_file(struct addrset *exclude_group, FILE *fp);
 int load_exclude_string(struct addrset *exclude_group, const char *s);