Strange entries in the LAN f/w blocked log

NogBadTheBad

They are Link-local unicast addresses fe80::/10, if you have multiple LANS add the following rules to each interface if you want to pass multicast traffic:-

lohphat

@nogbadthebad That's the thing, I only have one LAN i/f.

NogBadTheBad

@lohphat said in Strange entries in the LAN f/w blocked log:

@nogbadthebad That's the thing, I only have one LAN i/f.

~~Then just add the above rule and set it to block and not log if you don't want to see the entries in your firewall log :)~~

If your running AVAHI on the router you'll still need the rule regardless.

lohphat

@nogbadthebad So, for my IPv6-fu why weren't the fe80::/10 addresses local to the LAN segment not permitted by the IPv6 allow any any any rule in the first place?

NogBadTheBad

@lohphat said in Strange entries in the LAN f/w blocked log:

@nogbadthebad So, for my IPv6-fu why weren't the fe80::/10 addresses local to the LAN segment not permitted by the IPv6 allow any any any rule in the first place?

Because it's IPv6 local link rather than the IPv6 subnet you've defined on the LAN interface.

From my Mac:-

mac-pro:~ andy$ ifconfig en0
en0: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
options=10b<RXCSUM,TXCSUM,VLAN_HWTAGGING,AV>
ether 00:3e:e1:c1:af:07
inet 172.16.2.20 netmask 0xffffff00 broadcast 172.16.2.255
inet6 fe80::1cf1:d55:da78:975%en0 prefixlen 64 secured scopeid 0x6
inet6 2a02:xxxx:yyyy:2::14 prefixlen 64 dynamic
nd6 options=201<PERFORMNUD,DAD>
media: autoselect (1000baseT <full-duplex,energy-efficient-ethernet>)
status: active
mac-pro:~ andy$

2a02:xxxx:yyyy:2::14 is via DHCP

fe80::1cf1:d55:da78:975%en0 is set by the host

lohphat

@nogbadthebad So that raises an additional question: How does pfSense determine from a security perspective which link local addresses belong to which interface? Shouldn't it keep track as to which fe80:: addresses correspond to their associated i/f so that the rulebase can act accordingly? Or is the best practice to just block all fe80:: addresses and force the host to use their assigned real addressing? From my limited IPv6-fu I thought that the fe80:: addresses perform critical operations to keep multicast groups (e.g. NDP) working, so they need to be permitted.

NogBadTheBad

Link local are only needed on the local lan segment till you want multicast from one lan segment to another.

lohphat

@nogbadthebad So I modified the rule so that the FE80::%mvneta2/10 now includes the scope ID of the LAN.

So why aren't FE80:: addresses included in the LAN Segment and WAN Segment definitions by their scope ID so that they are covered by the rulebase for the segment since those packets originate there?

lohphat

@lohphat And THAT was a FAIL as the UI accepted adding the scope but the rule processor choked on it.

NogBadTheBad

@lohphat said in Strange entries in the LAN f/w blocked log:

@lohphat And THAT was a FAIL as the UI accepted adding the scope but the rule processor choked on it.

So what exactly did you put in ?

lohphat

@nogbadthebad allow IPv6(any) from-network fe80::%mvneta2 /10 to-network ff02:: /16

NogBadTheBad

@lohphat said in Strange entries in the LAN f/w blocked log:

@nogbadthebad allow IPv6(any) from-network fe80::%mvneta2 /10 to-network ff02:: /16

Look at my screenshot, it's fe80:: /10 -> ff02:: /16 and they're Networks !

lohphat

@nogbadthebad I saw that but the concern I have is that there are fe80 addresses on the WAN too. If I just want to permit fe80 traffic originating from the LAN i/f how do is that restricted? It seems your example permits any fe80 traffic no matter the origin.

NogBadTheBad

@lohphat

It won’t forward anything to the WAN.

You don’t enable AVAHI on the WAN interface do you?

lohphat

@nogbadthebad No. But I'm seeing link local addresses not in the NDP table. I'm concerned where they're coming from.

johnpoz

Then sniff and get the mac so you can track it down. link local is layer 2 only.. So if your seeing it on your lan - then it has to be from a device on the layer 2 your lan is connected to.

NogBadTheBad

You’ll see them on every segment with IPv6 enabled.

lohphat

@nogbadthebad That's my point. They're on every segment so how can I restrict source fe80 address which only exist on the LAN segment? I only have WAN adn LAN and I'm concerned about how to separate them instead of fe80 addresses being flat and not associated with an i/f in the ruleset.

NogBadTheBad

If you don’t enable AVAHI on the WAN interface they won’t be seen on the WAN interface.

You probably need to read up on mDNS and AVAHI.

lohphat

@nogbadthebad Well you CAN'T enable avahi on the WAN interface. It says so on the config page. I understand about mDNS and it's need to have multicast enabled.

This questions I have are more broad at this point.

I'm seeing fe80 addresses not in the NDP table. Where are they coming from?
If the fe80 packets are coming from the LAN interface then why isn't the LAN allow rule for IPv6(any) from-LAN to-any allowing them? Why aren't they included?