How to use 192.168... addresses behind Router with a Static IP

Hi,

I currently pay my ISP for a block of static IP addresses - I've assigned
one to my router/adsl modem, and one each to three other PCs. So these PCs
are currently accessible directly from the internet with external IP
addresses.

I'd like to just have one static IP address (it costs less) and still
operate my other PCs as I do currently.

I thought that the router would get the static IP address and then do
something to enable traffic to my other PCs. One PC publishes a small
website (currently accessible via its static IP address) and another PC I
use for Azureus.

I thought that with only one static, my other PCs would then have 192.168
addresses (either using DHCP from the router which is also a DHCP server or
manually configured). So if my webserver is on e.g. 192.168.1.99, how can I
still access it from the internet? Also, can I still use apps like Azureus?

Any help very much appreciated.

iceman

Use NAT and port-forwarding. Everything will be peachy, as long as you
don't have two servers requiring the same port, such as two
publicly-accessible web servers on port 80.

Hi

An External ISP type of IP cannot be configured to be use on the LAN side of
a regular Cable/DSL Router.

By using application that can be configured to use the ports of your choice,
you can use one External Static IP and direct the Traffic to the right
computer that is on an Internal IP (192.168.x.x).

This page was written for a specific application, but the principle might
apply to any application that interact through the Internet and has flexible
port configuration.

http://www.ezlan.net/vnc#portselect

Jack (MVP-Networking).





"iceman" <no.spam@please> wrote in message
news:(E-Mail Removed)...
> Hi,
>
> I currently pay my ISP for a block of static IP addresses - I've assigned
> one to my router/adsl modem, and one each to three other PCs. So these
PCs
> are currently accessible directly from the internet with external IP
> addresses.
>
> I'd like to just have one static IP address (it costs less) and still
> operate my other PCs as I do currently.
>
> I thought that the router would get the static IP address and then do
> something to enable traffic to my other PCs. One PC publishes a small
> website (currently accessible via its static IP address) and another PC I
> use for Azureus.
>
> I thought that with only one static, my other PCs would then have 192.168
> addresses (either using DHCP from the router which is also a DHCP server
or
> manually configured). So if my webserver is on e.g. 192.168.1.99, how can
I
> still access it from the internet? Also, can I still use apps like
Azureus?
>
> Any help very much appreciated.
>
> iceman
>
>

Jack (MVP-Networking). wrote:
> Hi
>
> An External ISP type of IP cannot be configured to be use on the LAN side of
> a regular Cable/DSL Router.
>

Oh yes it can! This is what routers are supposed to do, in the old
days, before NAT was invented. I guess today some consumer-level
routers have disabled this basic functionality. But my cheapo Aztech
DSL Router can do it. Routing != NAT. In fact, NAT has to be explicitly
enabled on a lot of routers to prevent external ISP type IP from being
used on the LAN.

You want to check out a site that has ALL computers
(servers/workstations/PCs) allocated an ISP type IP then check out my
alma mater: University of Essex. Each and every PC in the lab and in
offices runs on 'external' IP. I used to run ftp servers over the
weekends from the engineering lab ;-)

In fact the OP stated that that's how his current network is set up. So
it can be done and apparently works for him. He now wants to use NAT to
reduce his monthly bills.

> By using application that can be configured to use the ports of your choice,
> you can use one External Static IP and direct the Traffic to the right
> computer that is on an Internal IP (192.168.x.x).
>
> This page was written for a specific application, but the principle might
> apply to any application that interact through the Internet and has flexible
> port configuration.
>
> http://www.ezlan.net/vnc#portselect
>

Good suggestion.

Thanks for your help so far guys.

I would only have one web server on port 80, so no problem there.

However, I may have more than one PC on my LAN wanting to send and receive
email. Is this then going to cause a problem if both mail clients use the
same ports?

(Thinking about it, I've got quite a few apps that each PC would use - AVG
Virus updating, MS Antispyware updating, Spybot etc. Would there be a
problem there, or is it different because these apps initiate the
connection?)

iceman


"iceman" <no.spam@please> wrote in message
news:(E-Mail Removed)...
> Hi,
>
> I currently pay my ISP for a block of static IP addresses - I've assigned
> one to my router/adsl modem, and one each to three other PCs. So these
> PCs are currently accessible directly from the internet with external IP
> addresses.
>
> I'd like to just have one static IP address (it costs less) and still
> operate my other PCs as I do currently.
>
> I thought that the router would get the static IP address and then do
> something to enable traffic to my other PCs. One PC publishes a small
> website (currently accessible via its static IP address) and another PC I
> use for Azureus.
>
> I thought that with only one static, my other PCs would then have 192.168
> addresses (either using DHCP from the router which is also a DHCP server
> or manually configured). So if my webserver is on e.g. 192.168.1.99, how
> can I still access it from the internet? Also, can I still use apps like
> Azureus?
>
> Any help very much appreciated.
>
> iceman
>

Any modern NAT will also translate conflicting port numbers on outgoing
traffic. If two machines sent outbound traffic from port 1025, the NAT
would translate one of them to port 1026 for Internet traversal. Client
traffic will function quite nicely.

From: "iceman" <no.spam@please>

| Thanks for your help so far guys.
|
| I would only have one web server on port 80, so no problem there.
|
| However, I may have more than one PC on my LAN wanting to send and receive
| email. Is this then going to cause a problem if both mail clients use the
| same ports?
|
| (Thinking about it, I've got quite a few apps that each PC would use - AVG
| Virus updating, MS Antispyware updating, Spybot etc. Would there be a
| problem there, or is it different because these apps initiate the
| connection?)
|
| iceman
|

No. It's about incoming redirection. Outgoing is another story. It's not ant different
then ten PCs behind a NAT Router using TCPort 80 to Browse the web.

You can have upto 253 computers behind a NAT Router. All can can access Internet services
simultaneously and equally as well (not withstanding that the bandwidth is shared amongst
all LAN nodes).

--
Dave
http://www.claymania.com/removal-trojan-adware.html
http://www.ik-cs.com/got-a-virus.htm

Thanks again guys.

So, just to clarify. Apps that initiate internet communication (through the
router, using NAT) from the PC are not a problem at all.

The only issue is with regard to server functionality on my PCs - so if more
than one PC is providing the same server function (like a web server or ftp
server) then the router might have a problem performing NAT on INCOMING
internet transfers?

So if for each server function, it only exists on ONE of my PCs, I shouldn't
have any problem?

Cheers

"iceman" <no.spam@please> wrote in message
news:(E-Mail Removed)...
> Thanks for your help so far guys.
>
> I would only have one web server on port 80, so no problem there.
>
> However, I may have more than one PC on my LAN wanting to send and receive
> email. Is this then going to cause a problem if both mail clients use the
> same ports?
>
> (Thinking about it, I've got quite a few apps that each PC would use - AVG
> Virus updating, MS Antispyware updating, Spybot etc. Would there be a
> problem there, or is it different because these apps initiate the
> connection?)
>
> iceman
>
>
> "iceman" <no.spam@please> wrote in message
> news:(E-Mail Removed)...
>> Hi,
>>
>> I currently pay my ISP for a block of static IP addresses - I've assigned
>> one to my router/adsl modem, and one each to three other PCs. So these
>> PCs are currently accessible directly from the internet with external IP
>> addresses.
>>
>> I'd like to just have one static IP address (it costs less) and still
>> operate my other PCs as I do currently.
>>
>> I thought that the router would get the static IP address and then do
>> something to enable traffic to my other PCs. One PC publishes a small
>> website (currently accessible via its static IP address) and another PC I
>> use for Azureus.
>>
>> I thought that with only one static, my other PCs would then have 192.168
>> addresses (either using DHCP from the router which is also a DHCP server
>> or manually configured). So if my webserver is on e.g. 192.168.1.99, how
>> can I still access it from the internet? Also, can I still use apps like
>> Azureus?
>>
>> Any help very much appreciated.
>>
>> iceman
>>
>
>

Sounds 'bout right. The NAT will use port translation on outbound client
connections, so no worries there. You will be reduced to one public IP,
so you'll only have one of each port available for incoming server
connections. You could have two web servers accessible from the
Internet, but only one would be a able to utilize port 80. The other
would have to be on a different port.

From: "iceman" <no.spam@please>

| Thanks again guys.
|
| So, just to clarify. Apps that initiate internet communication (through the
| router, using NAT) from the PC are not a problem at all.
|
| The only issue is with regard to server functionality on my PCs - so if more
| than one PC is providing the same server function (like a web server or ftp
| server) then the router might have a problem performing NAT on INCOMING
| internet transfers?
|
| So if for each server function, it only exists on ONE of my PCs, I shouldn't
| have any problem?
|
| Cheers

Either the server would be placed in the DMZ of the Router or the protocol(s) of the service
would be port fowarded to the IP address of the server.

The problem arises if you have two http Daemons on two different platforms. Which one does
incoming port 80 go to ?

However, if one uses platform has a https Daemon the TCP port 80 incoming goes to one IP and
TCP port 443 incoming goes to another IP.


--
Dave
http://www.claymania.com/removal-trojan-adware.html
http://www.ik-cs.com/got-a-virus.htm