Realistic number of hosts for a /64 subnet?

Doug Barton dougb at
Fri May 10 06:27:22 CEST 2019

It's been a while since I was configuring subnets, and last time I did 
the guidance was always no more than 1,000 hosts per subnet/vlan. A lot 
of that was IPv4 thinking regarding broadcast domains, but generally 
speaking we kept to it for dual stacked networks, equating an IPv4 /22 
with an IPv6 /64. (This was commonly in office environments where we 
used a subnet per floor to accommodate all of the desktops, printers, 
phones, tablets, etc.)

Is this still how people roll nowadays? Have switches and/or other 
network gear advanced to the point where subnets larger than 1k hosts 
are workable? In IPv4 or IPv6? I've done quite a bit of web searching, 
and can't find anything newer than 2014 that has any kind of intelligent 
discussion of this topic.


More information about the ipv6-ops mailing list