Have WAN track WAN IPv6?
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Hello,
I have a DHCP /56 prefix delegation from my ISP. Is it possible to automatically assign an address from the PD to the WAN interface? I can add an alias to the WAN, but I would like it to update when the prefix changes.
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@mariatech Just select DHCPv6 for WAN, done.
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@bob-dig
On the WAN interface configuration page, "IPv6 Configuration Type" has been set to DHCP6. On the Status / Interface page, the WAN interface has only an fe80::/10 address. My prefix delegation is in 2000::/3, and pfSense does assign delegated addresses to other interfaces, but not to WAN. -
@mariatech What ISP and where do you live? It is often easier for others to help you with those information.
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@bob-dig What do we need to know about the ISP? They have provided a PD, and pfSense has accepted it. The ISP is not responsible for any configuration beyond that.
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If you need a destination for VPNs etc., you can use the LAN interface address. Makes no difference to the outside world.
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@jknott Thank you but the source address is actually more of a problem! Even the alias causes trouble, If I set one in the web UI, the link-local address on WAN gets deleted when dhcp6c renews.
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Perhaps I'm missing something, but what is it you're trying to do? A link local address on the WAN is normal and a global address is optional. If you're trying to connect to pfSense, it doesn't matter what interface an address is on, it will still be reachable from outside, assuming your firewall rules allow it.
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@jknott In short, I am trying to automatically assign a global IP address to the WAN interface. The address should track the prefix delegation obtained through DHCP.
When pfSense originates traffic, it needs to select a source address. The default gateway is on the WAN, so it will send the traffic through that interface. Since that interface has no global address, the kernel picks the longest match from some other interface, which may not be in the PD (e.g. addresses obtained through other ISPs or tunnels). Because the source address doesn't match the PD, it looks like a spoofed IP to the ISP ingress filter, and the traffic gets dropped.
The WAN interface also has hardware TCP and low-latency UDP, which need an address to listen for. The interface has a switch which can be programmed to get around this, but
ifconfig cxgbe1.0010 inet6 2___:_:_::abcd prefixlen 128seems to make things just work, although when I tried to add the alias in the web UI, sometimes the link local address on WAN just disappears.
according to dhcp6c.conf(5):
"dhcp6c will assign a prefix on the interface unless the interface receives the DHCPv6 message that contains the prefix with the delegated prefix"
Thus manually configuring dhcp6c.conf won't work.
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@mariatech said in Have WAN track WAN IPv6?:
When pfSense originates traffic, it needs to select a source address.
Whatever the source address, it will route appropriately. Also, is pfSense originating that much traffic? Other than a VPN or ssh, etc., I don't see much traffic coming from pfSense compared to something behind it. As for dhcpv6, it's already being used to get your prefix. Also, I don't know that it's advisable to put an address from within your prefix on the WAN side, as that WILL mess up routing, unless you create a specific route for that address.
Someone else has already tried my suggestion for using the LAN interface for a VPN and it worked for them.
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@jknott
Suppose the following configuration- WAN has link-local address fe80::q:r:s:t
- WAN has obtained a PD 2001:u:v::/48
- LAN tracks WAN, and is assigned 2001:u:v:1::aaaa and fe80::q:r:s:t'
- OPT is statically assigned 2600:w:z::bbbb/127
- the default route ::/0, obtained from the ISP RA is fe80::1 via WAN
Now suppose pfSense has to get something from files.netgate.com [2610:160:11:18::209]. This matches the default route, but since that interface has no global addres, the kernel will pick the longest match from the other interfaces. LAN's address matches the first byte of the destination, OPT matches the first two bytes, hence the source address will be OPTs.
Thus a SYN 2600:w:z::bbbb -> 2610:160:11:18::209 is sent to fe80::1 via WAN. Perhaps this is appropriate, but the ISP only expects to see packets from 2001:u:v::/48, so their ingress filter drops it. Even if fe80::1 were to forward it, the SYNACK would arrive on OPT, asymmetrically. Since pf wouldn't have a state on OPT for that connection, pfSense would drop the SYNACK at that point.
If 2001:u:v:2::cccc/128 were to be assigned to WAN, what would be messed up with the routing? The ISP has the route 2001:u:v::/48 -> fe80::q:r:s:t, everything on LAN has route ::/0 -> fe80::q:r:s:t', and the router on the other end of OPT doesn't need to talk to anything in 2001:u:v::/48 and has static routes to the loopbacks on pfSense. Who would need a specific route to 2001:u:v:2::cccc/128?
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It appears you're misunderstanding a few things. First, a link local default route is entirely normal and even if you had a global WAN address, it likely wouldn't be used for routing. All a router needs to know is how to get to the next hop. In fact an address isn't even necessary on a point to point link, where all you need is the interface. Second, all routing goes through the internal default route, which is 0.0.0.0/0 on IPv4 and ::/0 on IPv6. PfSense then determines which is the best interface to use. Since an external address does not appear on any interface, traffic for it is sent to your ISP's default route, which is the link local address.
As an experiment, go to the pfSense command line and enter:
ping -S <LAN IP address> google.com and see what happens. Try again with ping6. In this example, the ping is sent out with the LAN interface as the source address, not the WAN interface. It does not matter which interface address you use as a source, so long as it's on your pfSense box. -
$ ping -S 10.d.e.f google.com PING google.com (142.250.217.78) from 10.d.e.f: 56 data bytes 64 bytes from 142.250.217.78: icmp_seq=0 ttl=119 time=18.714 ms ... $ ping6 -S 2001:u:v:1::aaaa google.com PING6(56=40+8+8 bytes) 2001:u:v:1::aaaa --> 2607:f8b0:400a:80a::200e 16 bytes from 2607:f8b0:400a:80a::200e, icmp_seq=0 hlim=119 time=26.177 mshowever,
$ ping6 -S 2600:w:z::bbbb google.com PING6(56=40+8+8 bytes) 2600:w:z::bbbb --> 2607:f8b0:400a:80a::200e ^C --- google.com ping6 statistics --- 4 packets transmitted, 0 packets received, 100.0% packet loss $ ping6 google.com PING6(56=40+8+8 bytes) 2600:w:z::bbbb --> 2607:f8b0:400a:80a::200e ^C --- google.com ping6 statistics --- 4 packets transmitted, 0 packets received, 100.0% packet lossclearly the source address matters to ping6, and it automatically selects a source that doesn't work.
$ ifconfig cxgbe1.0010 | grep description\\\|inet6 description: WAN inet6 fe80::207:43ff:fexx:xx%cxgbe1.0010 prefixlen 64 scopeid 0x12 $ sudo ifconfig cxgbe1.0010 inet6 2001:u:v:2::cccc/128 $ ifconfig cxgbe1.0010 | grep description\\\|inet6 description: WAN inet6 fe80::207:43ff:fexx:xx%cxgbe1.0010 prefixlen 64 scopeid 0x12 inet6 2001:u:v:2::cccc prefixlen 128 $ ping6 google.com PING6(56=40+8+8 bytes) 2001:u:v:2::cccc --> 2607:f8b0:400a:80a::200e 16 bytes from 2607:f8b0:400a:80a::200e, icmp_seq=0 hlim=119 time=24.928 ms -
Well, I don't know what you're doing wrong as it works here:
ping6 -S 2607:fea8:4c82:5900:4262:31ff:fe12:b66c google.com
PING6(56=40+8+8 bytes) 2607:fea8:4c82:5900:4262:31ff:abcd:1234 --> 2607:f8b0:400b:80c::200e
16 bytes from 2607:f8b0:400b:80c::200e, icmp_seq=0 hlim=117 time=13.908 ms
16 bytes from 2607:f8b0:400b:80c::200e, icmp_seq=1 hlim=117 time=11.672 ms
16 bytes from 2607:f8b0:400b:80c::200e, icmp_seq=2 hlim=117 time=14.432 ms
16 bytes from 2607:f8b0:400b:80c::200e, icmp_seq=3 hlim=117 time=18.986 msIt works with 3 different interfaces, including a VLAN.
cxgbe1.0010 inet6 2001:u:v:2::cccc/128 <--- I'm not sure what you're trying to do here. I have a /128 on my WAN and it works fine. One thing about the /128 is it can never be used for routing, as there is only one possible address, which means there's no "other end" to the connection.
I suspect you have other issues causing this problem, as the -S works fine here for every interface I've tried.
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@jknott said in Have WAN track WAN IPv6?:
It works with 3 different interfaces, including a VLAN.
Do those interfaces share an ISP assigned prefix? How about
ping6 -S ::1 google.comcxgbe1.0010 inet6 2001:u:v:2::cccc/128 <--- I'm not sure what you're trying to do here.
I'm adding a global address to the WAN interface, as shown by the before and after ifconfig output.
I have a /128 on my WAN and it works fine.
By /128, do you mean global host address? I have shown that when I add a global address from my delegated prefix to the WAN interface, my system works fine too. The problem is that pfSense does not assign said address automatically. How did your WAN get its address?
One thing about the /128 is it can never be used for routing, as there is only one possible address, which means there's no "other end" to the connection.
I'm not sure what you mean by this. Other routers have my loopback /128 addresses as a destination. I do not expect nor want to make a direct connection to any other host in 2001:u:v:2::/64, a prefix of my WAN global address.
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@mariatech said in Have WAN track WAN IPv6?:
Do those interfaces share an ISP assigned prefix? How about
ping6 -S ::1 google.comYes. They're all part of the /56 I get from my ISP. Only the last 8 bits of the prefix change. For example, the prefix ID for my main LAN is 0, my VLAN, 3. etc. That ::1 is not a valid address for use over the Internet.
By /128, do you mean global host address?
The /128 means the size of the "network" is only 1 device, /127 provides 2, etc. If there is only one device, all that address does is identify the interface. My WAN address is also /128, which means it cannot communicate directly with any other address. As for those other routers, I bet they're using a link local address as happens here.
This is my default gateway from my ISP: fe80::217:10ff:fe9a:a199. The WAN /128 global address is not used for routing. It can be used as a target for VPN etc..
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Only the last 8 bits of the prefix change. For example, the prefix ID for my main LAN is 0, my VLAN, 3. etc. That ::1 is not a valid address for use over the Internet.
Hence all the source addresses from your ISP-assigned prefix will be acceptable to the ISP's router, and the responses will come back via the same gateway. When your pfSense automatically chooses a source address, it will be one of those, so it will always work. My pfSense has global addresses that do not belong to the default ISP, yet pfSense is selecting those addresses as the source and sending those packets to the ISP via the default gateway. The ISP's router will only forward packets originating from prefixes that the ISP owns, my packets are thus rejected, same as they would reject a packet having ::1 as the source.
My WAN address is also /128
My ISP does not assign any global address (NA), they only offer the PD through DHCP. All I am trying to do is to assign an address from the PD to the WAN, just like I can assign addresses to other interfaces with the 'track interface' option. I have demonstrated that manual configuration solves my source address problem without having to mess with the policy table. There have been no adverse effects wrt routing. The only negative is that if the alias is not removed before soliciting another lease, the interface goes into 'IFDISABLED' state, which has to be cleared before restarting dhcp6c.
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Why are you trying to use an address that's not provided by the ISP? The Internet routers won't know how to return replies to you. Where are you getting that address from? Since your ISP doesn't provide a WAN address, all you have to do is point to an internal address they do provide, as I have suggested.
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Why are you trying to use an address that's not provided by the ISP?
Because pfSense is a router
...all you have to do is point to an internal address they do provide, as I have suggested.
The DNS root servers, the package repo, NTP servers, ACME, etc. are internet resources, they are not hosted on my network.
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The prefix is used to find the network you're connected to. If you use an address from another network any packets that you're expecting will be sent to some other network.
The DNS root servers, etc. have absolutely nothing to do with this. If you take some address that does not belong on your network, the Internet will have no idea that you're using that address and will send all packets to that other network, no exceptions. For example, I'm on Rogers. If you were to use one of my addresses and you tried to do something on the Internet, I'd suddenly start receiving packets that I have no idea about and you'd be sitting there wondering why things don't work. They don't work because they can't work.
You cannot use those addresses while on your ISPs network, with the exception if you have a VPN to the network where that address belongs. In that case, the packets will be sent to that network and then forwarded over the VPN to you. I mentioned my prefixes earlier, where I have a /56 prefix. This provides me with 256 /64 prefixes, where the last 8 bits are used to determine which one. I use the highest one, "ff" for my VPN. So, I could take my notebook computer to some other network and connect to the Internet through my VPN, using an address within that ff network as my source address and everything will work fine. I cannot just take one of those addresses and assign it to my computer while on some other network and expect it to work.
Perhaps you should do some reading on how routing works.
