Multiple Static IPs through single DSL line, how to connect to devices from the outside?

Question

My boss had our DSL line converted to a Static IP so that we could hook up various devices (security camera DVRs) and be able to access them remotely.

Our ISP (AT&T/SBC) sent out a tech who installed a Motorola Netopia 3300-like DSL gateway (there are no model numbers on the box, but Google leads me to believe it's a Netopia 3300 series.) We have 4 static IPs, let's call them 11.22.33.44-48.

If a laptop (for example) is plugged-in to one of the four ports on the gateway, it will work perfectly fine once one of the static IP is manually entered into the laptop operating system's network config (along with the default gateway address and a subnet mask of 255.255.255.248.) At least "fine" as far as client applications go. It seems that outbound connections are working but inbound connections die somewhere before reaching their destination:

C:\Users\Andrew>tracert 11.22.33.44

Tracing route to 11.22.33.44 over a maximum of 30 hops

  1    <1 ms    <1 ms    <1 ms  192.168.1.1
  2    14 ms    14 ms    13 ms  adsl-blah-blah-blah   //A physically different DSL line from the one in question
  3    13 ms    12 ms    13 ms  dist2-vlan62.pltnca.sbcglobal.net [99.36.71.2]
  4    14 ms    13 ms    13 ms  ag2-10g0-12-3-0.pltnca.sbcglobal.net [151.164.103.2]
  5    33 ms    14 ms    14 ms  151.164.102.35
  6    14 ms    14 ms    15 ms  rback34-g1-1.snfcca.sbcglobal.net [206.13.3.68]
  7     *        *        *     Request timed out.
  8     *        *        *     Request timed out.
  9     *        *        *     Request timed out.
 10     *        *        *     Request timed out.
 11     *        *        *     Request timed out.
(etc)

If this were a standard DSL line plugged into a router, I'd assume that the proper ports aren't being forwarded or somesuch. This being something rather different than any connection I've worked with, I'm at a loss. The configuration page for the gateway has no settings for port forwarding. There is a setting for "pinholes" and I (think) I created pinholes for the needed ports, but to no avail.

Another thing I found was that devices connected to the gateway can talk to each other. For example I plugged the DVR into 11.22.33.44 and a laptop into 11.22.33.45 and was able to connect to the DVR and view the video streams, though I doubt any packets were leaving the building.

So, to make a long question short, how can I get inbound connections to work so that servers can receive connections on certain (or all) ports?

Answer 1

This is still a standard DSL line plugged into a router, the only difference is that the router is routing a block of IPs instead of a single IP. When you connect from one of your public IPs to another, they are still on the same subnet (based on the 255.255.255.248) so they will not pass out of the gateway, they will only be routed within the router. That said, if you can connect fine that way, and you cannot from outside, it is almost certainly a firewall issue. It will not be port forwarding as there is no NAT involved if you have public IPs.

On your traceroute, request timed out doesn't mean anything other than those routers either are not configured to respond to ICMP or they just dropped the packet due to having better things to do at the time. Can you get a traceroute to your IPs? That is what will matter for inbound connections (though I think you'll find it is hitting your router).

Try and disable the firewall completely for a short period of time and see if that makes any difference.