To bind IPs to your FreeBSD server:
Open /etc/rc.conf with your editor:
# vi /etc/rc.conf
You should see a line which looks like this:
ifconfig_fxp0="inet 66.96.xx.10 netmask 255.255.255.255"
where 66.96.xx.10 is the main ip address of your server.
Directly under it add this
ifconfig_fxp0_alias0="inet 66.96.xx.11 netmask 255.255.255.255"
Change 66.96.xx.11 to whatever your additional IP is.
If you have more then one additional IPs increase the number after alias for each ip
example:
ifconfig_fxp0_alias0="inet 66.96.xx.11 netmask 255.255.255.255"
ifconfig_fxp0_alias1="inet 66.96.xx.12 netmask 255.255.255.255"
ifconfig_fxp0_alias2="inet 66.96.xx.13 netmask 255.255.255.255"
ifconfig_fxp0_alias3="inet 66.96.xx.14 netmask 255.255.255.255"
ifconfig_fxp0_alias4="inet 66.96.xx.15 netmask 255.255.255.255"
ifconfig_fxp0_alias5="inet 66.96.xx.16 netmask 255.255.255.255"
ifconfig_fxp0_alias6="inet 66.96.xx.17 netmask 255.255.255.255"
ifconfig_fxp0_alias7="inet 66.96.xx.18 netmask 255.255.255.255"
etc…
Save the file and run /etc/netstart
#/etc/netstart
Thats it!