HFC NBN Connection Using Linux iPOE

My ISP changed my static IP , and at the same time my HFC protocol from PPOE to iPOE. This seems to be the result of a commercial arrangement wih another ISP

iPOE uses dhcp without a password, so my first attempt to connect was to use ifup-down. This did not work (failed to get a lease), but dhclient did. At first the connection was unreliable (leases lost), and some of the ports were masked out. Both these matters were raised with the ISP. The second matter was fixed immediately. I got no feedback on the first matter, but it seems to have beeen fixed,

The ISP's generally provide or sell preconfigured VDSL modems . In most cases the so called modem is only used as a router.

For HFC the NBN company provides and installs a "Cable Box" (aka "Cable Modem") which has an ethernet connection to the user.

It seemed a good idea to see if my existing firewall/NAT PC with its attached devices and Wifi hubs could simply be plugged into the HFC Cable Box. Fortunately this proved easy.

In the case of my ISP modems are sold configured for remote setup by the ISP.

It was necessary to set an iptables rule by issuing shell commands:

EXTIF=eth2
IPTABLES=/sbin/iptables
$IPTABLES -A FORWARD -o $EXTIF -p tcp -m tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu

Without this some websites had issues with TLS handshaking. Simply setting the MTU did not help. See Linux Advanced Routing & Traffic Control HOWTO

Wiring of Firewall PC

VOIP Telephone Connection