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Stupid question time. Is there anything in all this that can make my machine behind the router get the same address all the time? Do I manually assign it local

by howeyc 11y ago

Stupid question time. Is there anything in all this that can make my machine behind the router get the same address all the time? Do I manually assign it locally as with IPv4 and hope no one else in the building assigns the same IP? Is there anything to assign IP-to-Hostname at least on the local (behind the gateway) level. Or is this handled via some other service I need to run (maybe some server that runs dns and allows machines to push their desired hostname to it).

aidenn0 11y ago
There are multiple ways of assigning ipv6 addresses. The original way would actually give it the same address every time (48 of the lower 64 bits was based off of the MAC address and the remaining 16 bits were fixed). This has some privacy implications though (You now can be uniquely identified by the bottom 64-bits even when you change networks), so there are other ways of doing it, including a version of DHCP for ipv6.
g-clef 11y ago
you'd handle that in the same way you'd handle it in IPv4: either a static assignment & a tracking process to avoid collisions, or static assignments in DHCP. DHCP6 does exist, and static assignments within a DHCP scope is a very common feature. one caveat: DHCP6 is younger than IPv6, so not all router firmwares will have gotten around to implementing it yet.
rleigh 11y ago
It's done automatically by your router and your OS. By default you won't need to do anything--you plug it in and it just works. On the machine I'm writing this reply on, when I boot it up (with either FreeBSD, Linux or Windows) it gets a router advertisement from the router (which is routing both IPv4 and IPv6). It gets a standard NATed DHCP lease for IPv4. For IPv6, it combines the /64 network prefix assigned by my ISP with the NIC MAC address to compute a unique (and stable) address. There are of course alternatives. I can assign it statically, I can use privacy extensions to periodically change the address (seems to be the default on Windows for me) or I can use DHCPv6 to use DHCP-allocated addresses (my router doesn't support this though I have done it in the past with BIND).

by howeyc 11y ago

aidenn0 11y ago

There are multiple ways of assigning ipv6 addresses. The original way would actually give it the same address every time (48 of the lower 64 bits was based off of the MAC address and the remaining 16 bits were fixed). This has some privacy implications though (You now can be uniquely identified by the bottom 64-bits even when you change networks), so there are other ways of doing it, including a version of DHCP for ipv6.

g-clef 11y ago

you'd handle that in the same way you'd handle it in IPv4: either a static assignment & a tracking process to avoid collisions, or static assignments in DHCP. DHCP6 does exist, and static assignments within a DHCP scope is a very common feature. one caveat: DHCP6 is younger than IPv6, so not all router firmwares will have gotten around to implementing it yet.

rleigh 11y ago

It's done automatically by your router and your OS. By default you won't need to do anything--you plug it in and it just works. On the machine I'm writing this reply on, when I boot it up (with either FreeBSD, Linux or Windows) it gets a router advertisement from the router (which is routing both IPv4 and IPv6). It gets a standard NATed DHCP lease for IPv4. For IPv6, it combines the /64 network prefix assigned by my ISP with the NIC MAC address to compute a unique (and stable) address. There are of course alternatives. I can assign it statically, I can use privacy extensions to periodically change the address (seems to be the default on Windows for me) or I can use DHCPv6 to use DHCP-allocated addresses (my router doesn't support this though I have done it in the past with BIND).