diff --git a/bitflu.config.example b/bitflu.config.example
index 0fe39c1f4..55a5fd399 100644
--- a/bitflu.config.example
+++ b/bitflu.config.example
@@ -139,6 +139,10 @@ webgui_port               = 4081
 # Bitflus 'root directory'
 workdir                   = ./workdir
 
+# Support for ipfilter.dat files - needs Net::IPAddress::Filter::IPFilterDat
+# Filepath of filter list file.
+# ipfilter_dat_file         = ./ipfilter.dat 
+ipfilter_dat_file         =
 
 # Change uid/gid after startup (if started as root, needed for chroot)
 # runas_uid =
diff --git a/bitflu.pl b/bitflu.pl
index c4cda37e7..129187cee 100755
--- a/bitflu.pl
+++ b/bitflu.pl
@@ -1791,7 +1791,7 @@ package Bitflu::Network;
 use constant MAGIC_DSNUM  => 1024*0.75;     # Don't ask me why, but 0.75 makes our downspeed guess much better
 use constant KILL_IPV4    => 0;             # 'simulate' non-working ipv4 stack
 
-use fields qw( super NOWTIME avfds bpx_dn bpx_up _HANDLES _SOCKETS stagger up_q stats resolver_fail have_ipv6);
+use fields qw( super NOWTIME avfds bpx_dn bpx_up _HANDLES _SOCKETS stagger up_q stats resolver_fail have_ipv6 ip_filter);
 
 	##########################################################################
 	# Creates a new Networking Object
@@ -1835,6 +1835,20 @@ package Bitflu::Network;
 			}
 		}
 		
+        # Check whether to use an ipfilter.dat IP address filter.
+        if($self->{super}->Configuration->GetValue('ipfilter_dat_file')) {
+            my $ipfilter_dat_file = $self->{super}->Configuration->GetValue('ipfilter_dat_file');
+            eval {
+                require Net::IPAddress::Filter::IPFilterDat;
+            };
+            if ($@) {
+                $self->stop("Net::IPAddress::Filter::IPFilterDat is required for ipfilter.dat support.");
+            }
+            if ( ! -f $ipfilter_dat_file ) {
+                $self->stop("Unable to find ipfilter.dat file at '$ipfilter_dat_file'");
+            }
+        }
+
 		if(KILL_IPV4) {
 			$self->warn("IPv4 support is *DISABLED*");
 		}
@@ -1843,7 +1857,7 @@ package Bitflu::Network;
 	}
 	
 	##########################################################################
-	# Register Admin commands
+	# Register Admin commands. Load any IP filter file.
 	sub init {
 		my($self) = @_;
 		$self->info("IPv6 support is ".($self->HaveIPv6 ? 'enabled' : 'not active'));
@@ -1853,6 +1867,16 @@ package Bitflu::Network;
 		$self->{super}->Admin->RegisterCommand('netstat',   $self, '_Command_Netstat',   'Display networking statistics');
 		$self->{super}->Admin->RegisterCommand('dig',       $self, '_Command_Dig',       'Resolve a hostname');
 		$self->{super}->CreateSxTask(Superclass=>$self,Callback=>'_UpdateNetstats', Interval=>NETSTATS, Args=>[]);
+
+        # Check whether to use an ipfilter.dat IP address filter.
+        if($self->{super}->Configuration->GetValue('ipfilter_dat_file')) {
+            my $ipfilter_dat_file = $self->{super}->Configuration->GetValue('ipfilter_dat_file');
+            $self->info("Loading ipfilter.dat file '$ipfilter_dat_file'");
+            $self->{ip_filter} = Net::IPAddress::Filter::IPFilterDat->new();
+            $self->{ip_filter}->load_file($ipfilter_dat_file);
+            $self->info("IP address filter initialized");
+        }
+
 		return 1;
 	}
 	
@@ -2421,6 +2445,10 @@ package Bitflu::Network;
 			$self->debug("Won't connect to blacklisted IP $remote_ip");
 			return undef;
 		}
+		elsif($self->IpIsFiltered($remote_ip)) {
+			$self->debug("Won't connect to filtered IP $remote_ip");
+			return undef;
+		}
 		if(KILL_IPV4 && $self->IsNativeIPv4($remote_ip)) {
 			$self->debug("Will not connect to IPv4 addr $remote_ip");
 			return undef;
@@ -2482,6 +2510,10 @@ package Bitflu::Network;
 			$self->debug("Refusing incoming connection from blacklisted ip $new_ip");
 			$new_sock->close;
 		}
+		elsif($self->IpIsFiltered($new_ip)) {
+			$self->debug("Refusing incoming connection from filtered ip $new_ip");
+			$new_sock->close;
+		}
 		elsif(KILL_IPV4 && $self->IsNativeIPv4($new_ip)) {
 			$self->debug("Dropping new IPv4 connection from $new_ip");
 			$new_sock->close;
@@ -2657,6 +2689,24 @@ package Bitflu::Network;
 		}
 	}
 	
+    sub IpIsFiltered {
+		my($self, $this_ip) = @_;
+
+        return 0 unless $self->{ip_filter};
+
+        # Filter only supports IPv4
+        return 0 if $self->IsNativeIPv6($this_ip);
+
+        if ( !$self->IsNativeIPv4($this_ip) ) {
+            $this_ip = $self->SixToFour($this_ip);
+        }
+        my $is_filtered = $self->{ip_filter}->in_filter($this_ip);
+
+        $self->debug("Filtering $this_ip") if $is_filtered;
+
+        return $is_filtered;
+    }
+
 	
 	sub debug { my($self, $msg) = @_; $self->{super}->debug("Network : ".$msg); }
 	sub info  { my($self, $msg) = @_; $self->{super}->info("Network : ".$msg);  }