User comments on ISPs
  >> Eclipse Internet

Register (or login) on our website and you will not see this ad.

  Print Thread
Standard User Sodoshi
(newbie) Sat 20-Aug-11 11:02:47
Print Post

FTTC and Multiple Static IPs

[link to this post]
I recently migrated from Business Gold to Fibre Pro as I needed a speed upgrade. Migration went smoothly, apart from my need for multiple static IP addresses. Under ADSL with a DG834G this was a fairly benign thing to set up and configure - You simply set your WAN IP to the first of your statics, and your LAN IP range to be the rest of your statics. The router then dropped NAT and it all just worked.

Fibre... not so simple. You're given a choice between a Thompson and a Netgear router. (Unless you fork out for your own router.) Eclipse didn't tell me that neither allows for dropped/1-to-1 NAT, and the Eclipse customer services for FTTC are consumer orientated, so I gave up on phone support.

However, I did manage to work out how to achieve this (after nearly 2 weeks of pratting about and research) so this is what you need to do if you need the same sort of setup.

1. Take the Netgear WNR2000v2. (Do not take the Thompson. Although you can theoretically drop NAT on a Thompson, trying to configure the multiple virtual LANs and subinterfacing is an absolute nightmare(!))

2. Update the Netgear's firmware (using the Netgears default web interface) to DD-WRT. This is an alternate firmware that gives you a different web interface, but don't worry, its only mildly different. the setup/configure options are nearly identical to out-of-the-box Netgear. (At least the standard items.) The firmware you're looking for is dd-wrt.v24-14536_NEWD-2_K2.6_mini-WNR2000v2.chk and is available directly from the DD-WRT website.

3. Configure up and get on the internet as normal. The default internal IP for DD-WRT is onwards. Therefore you can configure up your internal network for DHCP on which will leave you for static IPs.

4. Set up your first PC you want to have a static IP using

5. telnet to and login with root and the password you gave your router

6. Enter the following 5 commands:

/sbin/ifconfig ppp0:1 x.x.x.x netmask broadcast x.x.x.175
/usr/sbin/iptables -t nat -I PREROUTING -d x.x.x.x -j DNAT --to-destination
/usr/sbin/iptables -t nat -I POSTROUTING -s -j SNAT --to-source x.x.x.x
/usr/sbin/iptables -I FORWARD -d -j ACCEPT
/usr/sbin/iptables -A INPUT -p icmp -j ACCEPT

Replacing x.x.x.x with your first static IP after your WAN IP, and the x.x.x.175 with the IP just after your range (the broadcast IP).

EG. If your range is then will be your broadcast.

See if your second WAN IP is pingable. if so, your PC is now on the internet with a static IP using 1-to-1 NAT. You can add extra IPs to other internal IPs by incrementing the ppp0 virtual interface. EG:

/sbin/ifconfig ppp0:2 x.x.x.y netmask broadcast x.x.x.175
/usr/sbin/iptables -t nat -I PREROUTING -d x.x.x.y -j DNAT --to-destination
/usr/sbin/iptables -t nat -I POSTROUTING -s -j SNAT --to-source x.x.x.y
/usr/sbin/iptables -I FORWARD -d -j ACCEPT

Where x.x.x.y is the second static IP after your WAN IP. The ICMP rule (the 5th rule in the first example) only needs to be run once, not after every additional IP.

Once you've practiced this (don't worry if you screw up, a reset will wipe the settings) you need to bake the script into the router:

7. Setting a script to do the above 30 seconds after the router boots up. (Giving it time to make a pppoe connection.) This is where I got stuck for ages - mainly because the router has only 16k of nvram and no internal storage. In the web interface of the router, under Administration, Commands, I saved the following as a firewall script:

NB: My additional IP range is x.x.x.162-174 (161 being the default WAN IP) so adjust your own script accordingly:

echo "sleep 30" > /tmp/
echo "for WANIP in 162 163 164 165 166 167 168 169 170 171 172 173 174" >> /tmp/
echo "do" >> /tmp/
echo "IFACE="\`"expr "\$"WANIP - 161"\` >> /tmp/
echo "LANIP="\`"expr "\$"WANIP - 160"\` >> /tmp/
echo "/sbin/ifconfig ppp0:"\$"IFACE x.x.x."\$"WANIP netmask broadcast x.x.x.175" >> /tmp/
echo "/usr/sbin/iptables -t nat -I PREROUTING -d x.x.x."\$"WANIP -j DNAT --to-destination 192.168.1."\$"LANIP" >> /tmp/
echo "/usr/sbin/iptables -t nat -I POSTROUTING -s 192.168.1."\$"LANIP -j SNAT --to-source x.x.x."\$"WANIP" >> /tmp/
echo "/usr/sbin/iptables -I FORWARD -d 192.168.1."\$"LANIP -j ACCEPT" >> /tmp/
echo "done" >> /tmp/
echo "/usr/sbin/iptables -A INPUT -p icmp -j ACCEPT" >> /tmp/
sh /tmp/ &

This effectively writes a script to the temporary folder on the router as the firewall starts, and executes it. after a wait of 30 seconds it runs a loop to set the rules we used above. I had to do it in a loop rather than just a big easier-to-read script due to memory on the Netgear. If you only have 2 static IPs, you probably don't need to worry so much.

Hope this helps someone. Good luck!

Edited by Sodoshi (Sat 20-Aug-11 11:08:31)

Standard User Istepper
(newbie) Thu 24-Nov-11 16:05:35
Print Post

Re: FTTC and Multiple Static IPs

[re: Sodoshi] [link to this post]
Hey... That's an amazing find but surely there must be routers out there which you can program more easily?

Its difficult , I know , I have been through three routers trying every conceivable combination of different things and the best I could come up with is a static address that wouldn't ping... So when is a static not an external static...? When it's a private static ! Which isn't what I want. I need to be able to ping from a different network .

If you know of any routers that would work for multiple external static IPs please let me know. I am trying to locate a server farm off one router. Thanks,
Standard User Sodoshi
(newbie) Thu 24-Nov-11 19:07:03
Print Post

Re: FTTC and Multiple Static IPs

[re: Istepper] [link to this post]
The post above maps multiple external static IPs 1 to 1 with multiple private static IPs.

In my case maps to and maps to and so on. Both internal and external are pingable.

Register (or login) on our website and you will not see this ad.

Administrator MrSaffron
(staff) Mon 28-Nov-11 14:56:00
Print Post

Re: FTTC and Multiple Static IPs

[re: Istepper] [link to this post]
If you mean the more standard NON-NAT mode, as opposed to what the original poster is doing then lots of routers can do this, and is a more common setup.

Andrew Ferguson, [email protected] - formerly known as
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
  Print Thread

Jump to