Bug #3657

Web Interface - Missing Static IPv6 /127 Subnet Prefix

Added by Cyril Tourist about 5 years ago. Updated over 4 years ago.

Web Interface
Target version:
Start date:
Due date:
% Done:


Estimated time:
Affected Version:
Affected Architecture:


Bug: When using the web interface (GUI) to configure a network interface with a static IPv6 the subnet prefix /127 is not available.

Workaround: Use the console (CLI) to configure the network interface.

Tested Affected Versions: 2.1.2 & 2.1.3

pfsense-ipv6-subnet-bug.png (15.8 KB) pfsense-ipv6-subnet-bug.png Cyril Tourist, 05/15/2014 04:26 AM

Associated revisions

Revision 8948f125 (diff)
Added by Chris Buechler over 4 years ago

Also include /127 for IPv6, it works fine. Ticket #3657

Revision 2727e3fc (diff)
Added by Chris Buechler over 4 years ago

Also include /127 for IPv6, it works fine. Ticket #3657


#1 Updated by Phillip Davis about 5 years ago

/usr/local/www/interfaces.php has code to specifically exclude 127:
for ($i = 128; $i > 0; $i--) {
if($i <> 127) {
echo "<option value=\"{$i}\" ";
if ($i == $pconfig['subnetv6']) echo "selected=\"selected\"";
echo ">" . $i . "</option>";

I wonder why that is?

#2 Updated by Doktor Notor about 5 years ago

@Phil: There was RFC 3627 ( especially discouraging the use of /127. It's now in historic status, see RFC 6547 ( The current document dealing with /127 appears to be RFC 6164 (

#3 Updated by Chris Buechler about 5 years ago

  • Affected Version changed from 2.1.2 to 2.1-IPv6

Because FreeBSD 8.x doesn't support it, the same as it doesn't support /31s. 10.x might support it, as it does support /31s, will need to be checked before changing the missing /127.

#4 Updated by Cyril Tourist about 5 years ago

We have successfully been using a IPv6 /127 subnet to connect our pfSense router with our ISP's router (COLT).
The use of a /127 was defined by COLT to connect our router with them.

The very very simplified setup looks something like this:
<ISP 'COLT' Router> [2001:920:X:X::24/127] <------> [2001:XXX:X:X::25/127] <pfSense Router> [2001:920:XXXX::1/48] <------> 2001:920:XXXX::/48 <Assigned /48 Subnet>

This setup has been working as expected (other then the GUI bug) with pfSense version 2.1 (FreeBSD 8.3-RELEASE-p11).
@Chris It would therefore seem that FreeBSD 8.3 supports /127 subnets?

#5 Updated by Chris Buechler over 4 years ago

  • Status changed from New to Resolved
  • Target version set to 2.2

this has been fixed in 2.2

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