Public static IPs from ISP don't work

[abu_shawarma]

I am assisting a friend with setting up public static IPs on 3 computers. He purchased 3 public IP addresses from the ISP and wants to use them on 3 different computers (2 PCs and a Mac). I entered in all the IP settings (ip address, subnet mask, gateway, DNS) exactly how it was given to me by the ISP into the wireless adapters settings. They are all on the same subnet. However, none of the computers will connect to the internet and they cant ping the gateway that the ISP gave us. We contacted the ISP's business technical support and their reasoning was because they were not hardwired to the modem/router. The PCs and modem/router are on different floors and my friend would like to be able to use the WiFi. He needs them set up with their own public IPs because he runs 3 separate businesses on them (I really don't know the full background of his businesses but that is what he requested.) I would appreciate any ideas to how to get this working, I think we/the ISP are missing something, probably simple too. Does the ISP's reason for them not working sound right? Sorry in advance if this was posted in the wrong thread.

[Georg Pauwen]

Hello,

what is the default gateway the PCs use, and on which device is the default gateway configured ?

[abu_shawarma]

the default gateway is what the ISP provided, for example the IP addresses were 78.x.x.50,78.x.x.51, and 78.x.x.52. The default gateway was 78.x.x.49. We just plugged in the IP information in the wireless adapter properties on each PC.

[paul driver]

@abu_shawarma wrote:

 I think we/the ISP are missing something, probably simple too. Does the ISP's reason for them not working sound right? Sorry in advance if this was posted in the wrong thread.

Its not the ISP, it’s the way you/your friend have set this up, you cannot just add those ip addresses to end host devices and expect them to work especially when they are in separate areas and not physically directly attached to the same subnet as the ISP.

As you are using wifi then the WLAN access point (s) or WLC need to be attached to the ISP network, then specific ssid that relates to the isp subnet created (suggest to isolate this connection via a DMZ)

If you are hard wiring the connection again you need a link to those end devices that shares the ISP subnet so its extended it towards those end nodes, Something like a switch(s) which could reach those areas

[abu_shawarma]

Why would it work hardwired to the router but not on the WiFi when it's being broadcasted from the same router? Isn't it still kind of "physically" connected? Sorry my networking knowledge is still beginner level.

[paul driver]

Hello,
As I stated the wifi needs to be directly connect to the isp somehow, and as you now say the wifi is intergraded into the router and that router is directly connected to the isp, then as long the ssid is setup correctly to accommodate the broadcast and the pcs adaptor support the network band, protocol and security type of the router then it should work.

[Martin L]

There usually is a modem box (cable or DSL modem) between your ISP and PCs.  What type of ISP connection do u have ?  Did them tell you type and modem details? If not, what modem do others in the building have?   Grab such modem and enter info you got from ISP into WAN side of things; while Private range IP LAN and Wireless SSID is on LAN side. 

Regards, ML
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[paul driver]

Hello @Martin L 

As the OP states public static addressing is to be used then it suggests the ISP connection to that WIfI/Router device is bridged as such no NAT would be performed by the ISP device, if any it would be downstream on that WIFI/router and for them to use those public IPs directly on their edge devices then their connection needs to on the outside any inside local LAN they may have set up.

[Richard Burts]

We do not know much about this environment and that limits our ability to give good advice. We do not know what device is connected to the ISP. But it sounds to me that some type of static NAT on that device translating the private (inside) IP to the public (outside) address would be the solution.