How works NAT??? 1

[DICS]

If the services address is in a different domain from the Control
Units IP address then NAT is automatically enabled.

I have done this, but in sysmonitor I see nothing.
-----------------
Service

IP Addr: 10.0.0.1 mask 255.255.255.252
__________
LAN

IP Addr: 192.168.0.1 mask 255.255.255.0

Some information about NAT appears in sysmonitor, when I delete services mask.

 

[Ragnorak]

I'm not really sure what you are asking, but here's some information on NAT and subnet masks that some people might find helpful even if it ends up having nothing to do with your question. My first impression is that you should not be using NAT.

First a little background. There are not enough IP addresses for every computer in the world to be connected to the Internet. To get around this they made certain IP addresses private. Private addresses will not be routed over the Internet. This allows people in different locations to use the same private IP addresses. 192.168.x.x and 10.x.x.x are private IP addresses.

NAT stands for Network Address Translation. It translates a private IP address into a public one. This allows one public IP address to be used by many private IP addresses. For example, all of the computers in an office will have 192.168.x.x addresses. There is 1 public IP address that comes with their DSL, cable modem, or T1 Internet connection. This Internet connection is plugged into a router that uses NAT. The router keeps track of each Internet request from inside the office and sends the repsonses back to the right computer, but to the Internet all traffic appears to come from that one public IP address.

The problem with NAT is that you can't directly access a computer with a private IP address over the Internet. You can only access the one public IP address of the router. In order to access the computers inside you need to build a VPN or use static port mappings.

Subnet Mask:
An IP address is actually two numbers. One is the network number and one is the computer number. The subnet mask tells you where to split the number. Take the IP address is 192.168.2.1 -- if the subnet is 255.255.0.0 then the network number is 192.168.0.0 and the computer number is 2.1 --- the same address with a subnet mask of 255.255.255.0 would be on the 192.168.2.0 network and the computer or node address would be 1.

More information than you need to know:
IP addresses go from 0-255 because they are actually binary numbers. 255 is 8 ones in binary. The subnet mask is a 32 digit binary number that is all ones then all zeros. This subnet mask gets compared to the IP address which is also really a 32 didit binary number. The part of the IP address that lines up with the ones of the subnet mask is the network number and the part that lines up with the zeros is the computer number.

 

[DICS]

Thank you for explanation! I understand principles of NAT working.

Its my fault that I have formulated question not exactly correct.

I make a test WAN PPP link between IPO and Definity through Cisco Router within my office. Therefore I use only private addresses.

When I enter IP Address (10.0.0.1) in service without mask, I can see at least NAT messages in sysmonitor.
I can ping only Definity and Ciscos porst from IPOs LAN (192.168.0.0/24), but not other computers in another LAN (172.16.0.0/24). LAN between IPO and Cisco - 10.0.0.0/30
Cisco doesnt see IPOs LAN generally, and I can establish telephone link from any side, but voice doesn`t go.

When I enter IP Address (10.0.0.1/30)in service with mask, I dont see NAT messages in sysmonitor, all works correctly. But there is no signs of NAT working - I can see IPOs LAN from Definitys LAN (imho I must see only public IPOs address 10.0.0.1).

 

[IPGuru]

I am not sure if NAT is actualy your problem , it sounds like a routing issue however

NAT is automaticaly activated on services that are given an IP address by the destination (IE an ISP or an IPO with DHCP active)

NAT is not enabled for destinations that do not issue an IP address (Ie an external router or IPO with DHCP disabled)

to use NAT on this sourt of connection yo need to go to the IP tab in the service & set the Originating IP Address & the SubNet Masc must be 255.255.255.255

the Origination IP address does not have to be an address on your local lan. for example in my servicers to connect to remotye sites I set IP to 192.168.99.1 this allows the remote IPO to talk back using the default IP route although my PC is on a completly different subnet.

 

[Ragnorak]

I think IPGuru is right.

"When I enter IP Address (10.0.0.1/30)in service with mask, I dont see NAT messages in sysmonitor, all works correctly. But there is no signs of NAT working"

"NAT is not enabled for destinations that do not issue an IP address (Ie an external router or IPO with DHCP disabled)"

Are you still having problems or are you just trying to understand the way IP Office uses NAT?

 

[DICS]

Thanks, now I have no questions.