I have a business class DSL line with AT&T and I have assigned to me a set of 5 static IP addresses that I need to setup for use. The account was recently changed over from a Standard DSL line with a dynamic IP to an account that now has these static IP addresses assigned to them.

This is needed so that some VOIP equipment that was purchased can have a static IP address assigned to it. Without doing any configuration changes on the wireless router (LinkSys E2500), the router is now getting the IP address that corresponds to the gateway that was assigned to my account.

My questions is, how do I go about assigning the static IP addresses to the other equipment on my network. The router I am using is pretty basic and the only option I am seeing in its settings for a static IP address allows me to enter 1 IP address and does not give me the option to configure PPPoE which is required by AT&T.

My assumption is that I will need to put a switch in between the dsl model and the wireless router and then plug in the VOIP device into that switch as well. I am hoping that my wireless router will than act as the gateway for the static IP addresses and then allow me to share the internet connection with the internal network. I will need to still route incoming connections to internal devices (remote desktop sharing, VPN) and this is where I am a bit fuzzy.

Since the wireless router I am using now has the gateway IP address, I would not believe I would be able to share that connection via NAT and since there does not seem to be any settings to manage more than one IP address I am wondering if this leaves me in a place where I will need more equipment. Can anyone add to advice or experience with a similar situation?


You need to put a switch on your DSL box.


Note: You don't have to use all your IP addresses. Only assign what you need to use.

There are plenty of networking devices out there that support multiple WAN connections (Cisco, SonicWall, ZyXel all have nice devices, which means you'll need to buy new equipment. As your network grows, you'll want to upgrade to better hardware to suit the needs of the environment).

Since you have a VOIP gateway, you'll want to separate the VOIP traffic onto it's own VLAN/subnet, separate from your data, to avoid quality and collision issues. So, an example would be

Router LAN:
Router Subnet:
Router WAN: [public ip 1]
Router Gateway: [DSL Box]

VOIP Gateway LAN:
VOIP Gateway Subnet:
VOIP Gateway WAN: [public ip 2]
VOIP Gateway Gateway: [DSL Box]    


From your question, it sounds like you want this kind of setup:


Just as a note about this, you wouldn't need multiple static IP addresses for this, but if you set up your network this way, your router would need to be able to manage multiple subnets on its own, and I don't think you'll be able to do that with a low class home user router. You'd need to buy a business class router for that.

If you buy a new switch to put in between your router, you could use the following example as your network setup:


  • So do I have to purchase a new switch for this configuration or can I just connect my current router to the switch (along with the DSL modem and VOIP gateway) and use it to do the PPPoE and share the internet connection with the LAN? – SYarman Oct 8 '13 at 17:12
  • See my updates. You have multiple options, but the simplest method would be to buy a new switch. The reason is, you're given a subnet of 5 public IPs to work with, but you only have a device that can handle 1 public IP on that subnet (everything connected behind that 1 public IP has to be translated to get internet access). If you add a switch, you allow more devices to communicate on that subnet by letting multiple machines share that subnet space without having to be translated (allowing you to use more than 1 public IP address in that subnet). – CIA Oct 9 '13 at 13:32
  • You have outlined the options very well. I understand what I have to do now to make this all work from a high level. I am going to give the dd-wrt firmware a try as well with my current router before buying another. From what I am reading that may give my current router the features it needs to handle multiple devices on the WAN without the need to purchase another router. Worst case scenario is that I have to buy a business class router but I may be even to get buy with an additional switch and basic router as well. Thanks for the input and I will bet back to you tomorrow with what works! – SYarman Oct 9 '13 at 18:05
  • I'm not sure you properly understood the diagrams. If your router only has 1 WAN port, you can only have 1 public IP address in use. If your VOIP gateway doesn't need a public IP, then you can keep using 1 router. If your VOIP gateway needs a public IP, then you need to buy a switch. As a professional note, it would be idea to separate your data network from your VOIP network, and following the 2nd example would work out best. – CIA Oct 9 '13 at 19:02
  • We got everything setup today. We ended up getting a new router that had a dsl modem built it (Netgear 7550). This router could be configured to setup its Ethernet ports as public lan ports allowing each device connected to it to be setup with one of the static ip addresses we were allocated. One IP was given to the VOIP box and another given to the existing router we were using previously to provide NAT to the internal network. The data network was also setup with separate VLANS, one for VOIP and one for data. Thanks again for your help. – SYarman Oct 10 '13 at 22:52

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