How to prevent auto config via SLAAC on a per Interfaces basis ?

RouterOS Beginner Basics
1

Dear,

I’m creating a more focused topic with a simple question
TLDR;

Q: What the recomended way to prevent a specific interface (in my case, a pppoe ‘parent’ interface) NOT to respond to SLAAC messages and not to assign itself an IPV6 address and configure routes ?

More details
http://forum.mikrotik.com/t/ipv6-macos-intermittent-packet-loss/176678/1 ( this topic is messy, no need to waste you time on my diagnose ramblings)

With the help of kind people on the forum, I managed to find the root cause of my sporadic packet loss: to many routing entries with same prio:

The parent interface of the pppoe session is assigning itself an IPV6 via slaac.

An additional routing entry is also created leading to routing incertainty.

I somehow managed to solve the issue by setting accept-router-advertisements=yes-if-forwarding-disabled

but this leads to the PPPOE interface not assigning itself an IPV6 via slaac.

According to RFC7084 requirement W-1, my router should behave like a “host” for the purpose of SLAAC ( IMHO, it thus should assign itself an address.)

thus my question: What t the “right” way and a more rfc compliant way of preventing the parent interface to assign itself an IPV6 address

2

When using PPPoE, it works just fine if you have settings as follows:

  • pppoe-client property add-default-route=yes
  • ipv6 settings property accept-router-advertisements=yes-if-forwarding-disabled
  • ipv6 dhcp-client property add-default-route=no (this is default setting)

Things get tricky when WAN interface is “plain” ethernet with DHCPv6 client running … one can try with add-default-route=yes which may or may not work as desired. But in this case, proper solution is to set ipv6 settings accept-router-advertisements=yes … but you’re saying that his doesn’t work correctly.

But in any case it’s very tricky if one has multiple WAN Interfaces. Or if one has LAN Interfaces with clients sending out RAs (which properly working clients should not).

You can try to block routing advertisements in firewall raw, check this post for slightly more info about that.

3

Thanks you for your answer.

I tried blocking the ICMPV6 on the parent interface, but it looks like it also blocked it on the pppoe interface.

My current settings match your advice. Let’s keep it like that for now!

Thanks a Lot