I wish to host a SIP server and DNS at the end of an ADSL2 connection. My current network sits behind an iptables firewall which runs on a Linux box with two Ethernet interfaces, the WAN interface (eth0) connecting to my ISP via an ADSL modem which once the PPPoA negotiation is over is essentially transparent. The LAN side of the firewall (eth1) currently runs the RFC1918 range 10.0.1/24 which is NATed through the firewall with no problems with everything masquerading through the single static public IP address my ISP has allocated me.
I have now been allocated a /29 by my ISP: x.y.z.104/29 - so x.y.z.104 to x.y.z.111 with .104 being the network and .111 the broadcast addresses respectively. My ISP has allocated the .110 address as the router: i.e. this is the public address my MODEM picks up when it connects to the ADSL network and which it allocates eth0.
I need to configure things such that traffic to the servers behind the firewall which have public IP addresses is routed in and out correctly but that the 10.0.1/24 range still masquerades correctly. Could this be done just with iptables or would I also have to define some sort of static route? Would eth1 also have the x.y.z.110 address allocated to it like eth0 has (my ISP has suggested this)?
Also, the firewall would need to be configured to allow inbound SIP and RTP connections to my SIP server/ip pbx (Asterisk). Is iptables the correct tool for the job or should I be looking elsewhere?