mal.hub...@bt.com wrote on 02/09/2019 17:55:
Hey,
Mal here. IETF attendee since 2012 ;)
I have a home networking question with respect to IPv6 standards, I’m
hoping to use you as a sounding board first before I take it to v6ops.
The scenario here is a home / soho network situation where the user
wants to host a service, lets say its a webserver, but really could be
any hosted application, importantly using IPv6. The router is setup to
use SLAAC only.
The ISP offers IPv6 GUA addressing in a non-stable manor, its "sticky"
but at some point in the future it might change (BNG reboot for example),
IMHO Expected behavior. Many European data protection people consider an
IP(v6) address to be privacy-sensitive personal data.
That will likely mean regular renumbering of IA PD by ISP's as the norm
rather than the exception.
so the user will use DynDNS provider to provide a stable name for
their service, this sounds OK so far.
External users should also be using a name rather than a (time variant)
IPv6 address.
Please be so kind as to review our draft
https://tools.ietf.org/html/draft-ietf-homenet-front-end-naming-delegation-08
[Hopefully a new version will be forthcoming soon]
This is precisely one of our use-cases.
The user has to allow the webserver port, 443 in their router GUI
firewall to allow the traffic in, sounds simple enough. Importantly it
should be to that webserver device only.
Now the tricky part….
Since in this scenario the webserver device is using privacy
extensions, it has a bunch of IPv6 GUA addresses and no EUI-64 and
- It has Temporary addressing (which will regularly change)
- It has a "Permanent" address (which is the one the webserver will
want to use)
The webserver should not be using privacy extensions for inbound sessions.
It really should be using https://tools.ietf.org/html/rfc7217
Does this sound reasonable and make sense so far ? Cool.
In the router GUI the user is presented with a list of "devices" for
which the router can open up TCP 443 in the firewall.
It is reasonable to assume the user does not want to type in the
Permanent IPv6 address of the device, as it is poor CX and anyway it
will change in the future (possibly due to a network change / BNG
restart etc as mentioned)
Correct.
Current routers on the market I have come across have either:
1. Open the port to the current temporary address only which means
that inbound connections on the port usually fails right away (if
the webserver is not listening on that address) – or fail after
the temporary address changes.
2. Opens the port to the correct address (by chance)
1. - But then fails at some point in the future when the network
prefix changes (as router drops the rule when the prefix changes).
3. Opens the port to some or ALL addresses currently (& sometimes
historically) associated with the mac address of the device (not
great for security – spoofing? )
1. But even that sometimes excludes the permanent address
4. Opens the port to all addresses on LAN (not great for security at all)
* Basically the routers firewall config gui doesn’t know reliably
which device address is the permanent one.
* Should there exist a mechanism to signal to the router or the
router can accurately learn which of the devices addresses should
be used for configuration in the firewall ?
Yes. via PCP RFC6887 et al.
*
Is this a problem – have I missed something – Is it worth fixing ?
Yes. - RFC8520? although there's still a gap for policy IMHO (does a
user want to accept what the manufacturer suggested) - Yes.
Thoughts:
This is probably a strange thing for the user to do (but I have had
users trying to do it). Its usually fixed for a customer by switching
off privacy extensions / using EUI-64 so basically giving the device a
single address for the router gui to identify the device by.
I personally hope this becomes more common, to avoid the need for NAT,
rendezvous points, dependence on central certificate instances etc.
Mal
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--
regards,
RayH
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