diff --git a/net/net-lib.pl b/net/net-lib.pl
index 69d3c1391..372dc3325 100755
--- a/net/net-lib.pl
+++ b/net/net-lib.pl
@@ -403,5 +403,32 @@ else {
 	}
 }
 
+# canonicalize_ip6(address)
+# Converts an address to its full long form. Ie. 2001:db8:0:f101::20 to
+# 2001:0db8:0000:f101:0000:0000:0000:0020
+sub canonicalize_ip6
+{
+my ($addr) = @_;
+return $addr if (!&check_ip6address($addr));
+my @w = split(/:/, $addr);
+my $idx = &indexof("", @w);
+if ($idx >= 0) {
+	# Expand ::
+	my $mis = 8 - scalar(@w);
+	my @nw = @w[0..$idx];
+	for(my $i=0; $i<$mis; $i++) {
+		push(@nw, 0);
+		}
+	push(@nw, @w[$idx+1 .. $#w]);
+	@w = @nw;
+	}
+foreach my $w (@w) {
+	while(length($w) < 4) {
+		$w = "0".$w;
+		}
+	}
+return lc(join(":", @w));
+}
+
 1;
 
diff --git a/webmin/change_bind.cgi b/webmin/change_bind.cgi
index 100d8749c..89feca0cc 100755
--- a/webmin/change_bind.cgi
+++ b/webmin/change_bind.cgi
@@ -61,13 +61,14 @@ if (@ips && &foreign_installed("net")) {
 		foreach $a (&net::active_interfaces()) {
 			$onsystem{$a->{'address'}} = $a;
 			foreach $ip6 (@{$a->{'address6'}}) {
-				$onsystem{$ip6} = $a;
+				$onsystem{&canonicalize_ip6($ip6)} = $a;
 				}
 			}
 		}
 	if (%onsystem) {
 		foreach $ip (@ips) {
-			$onsystem{$ip} || &error(&text('bind_eonsystem', $ip));
+			$onsystem{&canonicalize_ip6($ip)} ||
+				&error(&text('bind_eonsystem', $ip));
 			}
 		}
 	}