Routing a Static IP without a Gateway Address

[TechBoi-215]

Good morning/afternoon,


I have a firewall that I am setting up and my ISP has provided me with a static IP. I want to put the modem/router that they have provided me into true bridge mode. I was told that they provided me with a certain address range which consist of xxx.xx.93 (Network Address), xxx.xx.94 (Usable Static IP Address) and xxx.xx.95 (Gateway Address). Is it possible for me to set a static IP address to a device on my network whilst putting the modem they gave me into bridge mode? I was told that the router functionality will be disabled and it will just be a pass through

 

[bill001g]

You should be able to connect your pc. That is a strange ip range. If the subnet mask is 255.255.255.252 which would be common if they only gave you 1 ip. The network would be 92 and the gateway would be 93 or 94 and the other would be your ip and 95 would be the broadcast.

 

[Rookie_MIB]

Who do you have the internet service through? I have a business class account through Comcast, and I have their gateway, with 13 statics.

One of the statics is the router. (.145)
Two of the others point to my DNS server. (.157/.158)
The rest point to various websites on the webserver. (.146-.156)

The gateway also has a statically assigned IP address internally (192.168.254.100) and the DHCP assigns IP addresses in the 192.168.254.1-99 range. Everything else over that is statically assigned and doesn't move (NAS, network printer etc).

I guess my question is - why would you want to put it in bridged mode? Keeping it as the router for the internal network should have no effect on where the static IPs wind up going.

 

[TechBoi-215]

You should be able to connect your pc. That is a strange ip range. If the subnet mask is 255.255.255.252 which would be common if they only gave you 1 ip. The network would be 92 and the gateway would be 93 or 94 and the other would be your ip and 95 would be the broadcast.

That was actually just an example range. I'm not connecting the modem/router that I am using as a pass through (Bridging) to a computer. I will be connecting my firewall to it though. Without the gateway address set to device they provided me?

 

[bill001g]

The gateway address is their ip....it is where you send things (ie the gateway) to get out of your location to the internet.

 

[TechBoi-215]

The gateway address is their ip....it is where you send things (ie the gateway) to get out of your location to the internet.

So without the gateway address within that range that they gave me, I won't be able to route the usable static correct?

 

[bill001g]

There is always some form of gateway ip you must send you traffic back to.

When you have only 1 ip you are going to have to use some form of NAT if you put a firewall or router in between. There is only 1 ip and only 1 device (in this case the firewall) must own that. You can not actually assign it to the end server directly.

The way it is done when you need to assign it to the end server they would assign a different IP to your router and then route a block of ip to you. There are many other messy ways I have seen this done say on att uverse where they assign them all to their special router and you end up doing multiple 1-1 nats.