Subj : Re: Housekeeping
To   : 2twisty
From : deon
Date : Tue Jul 12 2022 09:05:00

  Re: Re: Housekeeping
  By: 2twisty to deon on Mon Jul 11 2022 09:08 am

 >  de> I reckon they should just set a date to stop routing IPv4 and let everybody scramble to get IPv6 going.
 >
 > Probably the best choice...  But I have never been able to wrap my brain around IPV6.  I even struggle with subnetting in IPV4.
 >
 > I've never really found a good source to teach IPv6 that doesn't rely on a strong understanding of IPv4.

So for the majority of use cases, IPv6 is a hands off operation.

Your router discovers the "subnet" allocated to it.

Your router feeds the devices in your lan an IPv6 address automatically (discovery)

If you want to split your subnet up because you have multiple lans, then "smart" routers can do that too - although I must admit its a bit hit and miss sometimes (what I want, and what I get can be 2 different things).

If you want to go manual, and configure everything yourself you can - but yes, the knowledge required is higher than that of IPv4 (IMHO).

But with both IPv4 & IPv6, you take the "subnet" and the "mask" to get 1 answer - is this packet destined to somebody on my LAN, or do I need to give it to another router (that makes the same decision)? If the packet is destined for the LAN, the kernel drops the packet on the wire with the destinations address. If it isnt, its dropped on the wire with the router's address - where the router picks it up and makes the same decision.

There is a useful tool called "ipcalc" which enables you to see what address range is "local":

╰─$ ipcalc 10.1.0.0/24
Address:   10.1.0.0             00001010.00000001.00000000. 00000000
Netmask:   255.255.255.0 = 24   11111111.11111111.11111111. 00000000
Wildcard:  0.0.0.255            00000000.00000000.00000000. 11111111
=>
Network:   10.1.0.0/24          00001010.00000001.00000000. 00000000
HostMin:   10.1.0.1             00001010.00000001.00000000. 00000001
HostMax:   10.1.0.254           00001010.00000001.00000000. 11111110
Broadcast: 10.1.0.255           00001010.00000001.00000000. 11111111
Hosts/Net: 254              Class A, Private Internet

There is a similar version for IPv6 - but I use https://www.vultr.com/resources/subnet-calculator-ipv6/


....δεσ∩
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