This page lists the problems we have found and raised regarding the ZyXEL VMG1312.

Problem List

TL;DR (Brief overview of the problems listed below)

The main problems are:

Ethernet port 1 can't be used, don't plug a device in to this port, hoped to have a firmware update in April
MTU 1500 is not supported on some setups (Internet access will still work fine, but we'd like 1500) - Still under evaluation with ZyXEL, may or may not happen.

Bridging 1508 bytes ethernet

Issue Description

We need the router to support baby jumbo frames bridging to VDSL and ADSL, to support *at least* 1508 bytes to allow RFC4638 PPPoE to a connected device.

Date Reported

2015-02-19

Updates

2015-02-19 ZyXEL development team aware, and are looking in to whether they can support this feature. 
2015-03-28 Still ZyXEL HQ are still evaluating the effort to make this change.

Resolution

None yet.

IPv6 RA on LAN

Issue Description

We are seeing a slight issue with IPv6 RA on the LAN. We are getting a prefix from the PPP link on VDSL. When PPP comes up, several seconds later the router does a DHCPv6 on the WAN, and then does an RA on the LAN, which works. We are puzzled by the noticeable delay in DHCPv6 PD which delays IPv6 connectivity. If PPP drops for any reason it appears to withdraw the RA on the LAN immediately, which is fine. However, when PPP reconnects it does not re-send the DHCPv6 on the WAN. This may be deliberate, and in our case it is probably OK, but it is something of an assumption that the previous DHPCv6 remains valid on the PPP after a reconnect. I'd suggest a new WAN RA/DHCPv6 immediately on every reconnect. Also, it seems not to send an RA on the LAN again for some minutes. This means there is a significant gap in IPv6 availability if there is a PPP drop from any reason.

Date Reported

2015-02-19

Updates

2015-02-19 In hand with ZyXEL.

Resolution

None yet.

Port 1 - Ethernet settings wrong

Issue Description

It seems to be set to 100M fixed with no auto-negotiation. This results in a duplex mismatch when used with any auto-config port and results is slow speed and poor performance.

Date Reported

2015-02-16

Updates

2015-02-18 Inhand with ZyXEL.
2015-03-18 New firmware hopped for April
2015-04-14 New firmware available which fixes this issue

Resolution

Firmware: V1.00(AAJZ.5)b1| 03/13/2015 has the following release note:

[BUG FIX]1.[ITS:#141200518][TSF] VMG1312-B10A LAN1 interface speed issue.

MLD snooping

Issue Description

There is no way to enable MLD snooping on the LAN interface group without also enabling the router's Router Advertisement feature. This contrasts to IPv4, where I can disable the router's DHCP server but still enable IGMP snooping.

Date Reported

2015-03-06

Updates

None yet.

Resolution

None yet.

UDP Deafness

Issue Description

Seems to sometimes "go deaf" to certain UDP packets, which has the side effect of breaking VPNs and/or DNS in the same way as the BT Huawei modems did (https://aastatus.net/1854). Power cycling clears it. This has been seen on one staff line a couple of times. ZyXEL is in bridge mode, and TCP DUmp on the FireBrick router shows port 53 UDP going out, and a dump on the AAISP end (via Clueless) does not see the packet. It seemed that the ZyXEL had blocked the FireBrick router from sending DNS, yet other machines on the LAN could still send DNS queries successfully.

Date Reported

2015-04-07

Updates

As this is rather intermittent, we've not yet reported it to ZyXEL - awaiting further examples.

Resolution

None yet.

Template to use for new problems

Issue Title

Issue Description

Description of Issue.

Date Reported

2015-00-00

Updates

None yet.

Resolution

None yet.