Set ipv6only option in your dhcp server.
If its value is set to 0xffffffff, dhcp client should not try again.
If it was below max value, it should wait and try again at least
MIN_V6ONLY_WAIT (300) seconds to send another request.
In both cases, it should go_daemon.
```
% mdo dhclient bridge0
DHCPDISCOVER on bridge0 to 255.255.255.255 port 67 interval 7
DHCPOFFER from 100.64.1.254
IPv6-Only Preferred option received (300 seconds), abort
```
If option sets after dhclient get bounded, it will renew,
even if the option added later to dhcp server.
```
DHCPDISCOVER on bridge0 to 255.255.255.255 port 67 interval 3
DHCPOFFER from 100.64.1.254
DHCPREQUEST on bridge0 to 255.255.255.255 port 67
DHCPACK from 100.64.1.254
bound to 100.64.1.125 -- renewal in 300 seconds.
DHCPREQUEST on bridge0 to 100.64.1.254 port 67
DHCPACK from 100.64.1.254
bound to 100.64.1.125 -- renewal in 300 seconds.
```
So, normally existing clients shouldn't react to option since they simply
send a DHCP REQUEST to renew and we only react to DHCP ACK if we're in INIT-REBOOT state.
```
% mdo cat /var/db/dhclient.leases.bridge0
lease {
interface "bridge0";
fixed-address 100.64.1.125;
next-server 100.64.1.254;
option subnet-mask 255.255.255.0;
option routers 100.64.1.254;
option domain-name-servers 100.64.1.53,9.9.9.9;
option domain-name "spmzt.net";
option dhcp-lease-time 600;
option dhcp-message-type 5;
option dhcp-server-identifier 100.64.1.254;
option ipv6only 4095;
renew 6 2026/4/25 20:32:56;
rebind 6 2026/4/25 20:36:41;
expire 6 2026/4/25 20:37:56;
}
[pouria@cornelia] [/usr/src] [rfc8925|✔] % mdo dhclient bridge0
DHCPDISCOVER on bridge0 to 255.255.255.255 port 67 interval 6
DHCPOFFER from 100.64.1.254
IPv6-Only Preferred option received (4095 seconds), abort
```
If compiled without netlink support, it assumes we don't have connectivity
and ignores the option.