How do I start hpux network service?

Use following command to start HP-UX network service:

/etc/init.d/net start
OR
/sbin/init.d/net start
Please note that your network configuration file is /etc/rc.config.d/netconf . Here is my sample /etc/rc.config.d/netconf file:

# cat /etc/rc.config.d/netconf
Output:
HOSTNAME=deephpux < --change hostname here OPERATING_SYSTEM=HP-UX LOOPBACK_ADDRESS=127.0.0.1 INTERFACE_NAME[0]=lan0 IP_ADDRESS[0]=192.168.1.100 <--change IP address here SUBNET_MASK[0]=255.255.255.0 <--change subnet mask here BROADCAST_ADDRESS[0]="" DHCP_ENABLE[0]="0" <--Do you wanna DHCP? set 1 to use DHCP

You can also set IP address using ifconfig command:
# ifconfig lan0 192.168.1.200 netmask 255.255.255.0 up

See or get current IP address information with ifconfig command:
# ifconfig lan0

For more information see the summery of HP-UX networking related tools and commands.