Multi physical interface with same subnet
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My (very old) machines have fixed IP…
My network experience goes back to 1978 and on a lot of different systems. I don't think I've ever seen something where an address couldn't be changed. If someone actually created such a device, they should be shot for incompetence. ;)
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Yeah same here.. I was working in networking and computers before there was IP… Have never seen such a thing - even in manufacturing and test equipment.
Only thing I can think of some sort of license tied to an IP.
I remember like it was yesterday having to go around and install tcp/ip on the windows 3.11 machines as we were moving to that from ipx/spx
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Yeah same here.. I was working in networking and computers before there was IP
Apollo Token Ring, IPX & Appletalk here :)
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Yeah same here.. I was working in networking and computers before there was IP
Apollo Token Ring, IPX & Appletalk here :)
The first LAN I worked on was part of the Air Canada reservation system in Toronto. It used time division multiplexing, that is time slots, instead of packets. A device with data to send was assigned (usually permanently) a time slot to transmit and the destination would then listen on that time slot. There were 2 networks. The main "TDX" ring ran 8 Mb/s over tri-axial cable and the older TDM ring, 2 Mb over coax.
Even on that ancient equipment, it was possible to change the device address. -
Yes, you are right, it's possible to change the IP on these machine, but I can't as they are not mine and the owner doesn't want to. It seems complicated for him (old machine), and after use it on my network he wants to use it with this address without changing anything.
Any idea if it's possible to use only 1 router for this config?
Even if my configuration seems strange for you :o -
How? When the router has a packet for 192.168.10.1 how is it supposed to know which interface to send it on?
Tell your customer what's what.
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How? When the router has a packet for 192.168.10.1 how is it supposed to know which interface to send it on?
Tell your customer what's what.
Well, machine can't be accessed by wan or the other lan, so if the router can NAT each machine differently knowing that machine are on different lan and interface…
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Yes, you are right, it's possible to change the IP on these machine, but I can't as they are not mine and the owner doesn't want to. It seems complicated for him (old machine), and after use it on my network he wants to use it with this address without changing anything.
Well, it's then your responsibility to advise him. Wishful thinking doesn't get very far, when it contradicts reality.
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@jaf:
How? When the router has a packet for 192.168.10.1 how is it supposed to know which interface to send it on?
Tell your customer what's what.
Well, machine can't be accessed by wan or the other lan, so if the router can NAT each machine differently knowing that machine are on different lan and interface…
NAT still has to know which interface to use. If the same address is on both sides, how does it work?
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So let me get this right… There are more than one machine, and they both have 192.168.10.1 and you want to give them both internet access. And you think it would be easier to run 2 pfsense boxes vs just having them change the IP of the one of these machines?
At a total loss here..
"the owner doesn't want to"Then tell him he can not be on your network ;)
What is the relationship here - are you the customer, he is the customer? Do you need this on your network, or does the owner?
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So let me get this right… There are more than one machine, and they both have 192.168.10.1 and you want to give them both internet access. And you think it would be easier to run 2 pfsense boxes vs just having them change the IP of the one of these machines?
At a total loss here..
"the owner doesn't want to"Then tell him he can not be on your network ;)
What is the relationship here - are you the customer, he is the customer? Do you need this on your network, or does the owner?
Yes, he is my customer, and customer is king…
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He is your customer.. Why would he think he could connect to a network and not change the IP on multiple machines all having the same IP? So while he is king, he is also mentally challenged when it comes to networking..
Why is the box not just dhcp? I mean really set it to dhcp and there you go done.. You can have as many boxes then without any issue.
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Yes, he is my customer, and customer is king…
And if what he wants is impossible? Assuming you set up NAT. You will have 2 devices with the same IP address, but on opposite sides of it. When the device behind NAT has traffic for it's twin on the outside, it will never leave that device, as it will assume it for itself. When some other device has traffic for the device behind NAT, NAT will then have to decide which way to send the traffic. It does this by comparing the destination address with the network addresses. If both networks have the same address, there is absolutely no way for NAT to know which way to send that traffic. What that customer wants is impossible. King or not he has to be told and hopefully you won't lose your head! ;)
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Its not impossible just stupid… You would have to it like he showed with different nat device for very box that wants to use 192.168.10.1 so you could nat it to a different network..
Each box would have to be isolated from each other on their own network with a different nat box. Utterly moronic...
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He is your customer.. Why would he think he could connect to a network and not change the IP on multiple machines all having the same IP? So while he is king, he is also mentally challenged when it comes to networking..
Why is the box not just dhcp? I mean really set it to dhcp and there you go done.. You can have as many boxes then without any issue.
Sorry, I can't give here the full context of my customer. But believe me, if I ask this question, it's because I really need this configuration. If I can do it differently, I will do!
What that customer wants is impossible. King or not he has to be told and hopefully you won't lose your head! ;)
Sorry, I don't understand why it's impossible. Do you agree it's possible at least with 2 routers?
If not, I don't understand what's the purpose of lan with NAT if all lan must have strictly different subnet and address? -
You can do it - you would just need a box to nat every single box that wants to use the same address so you can put them all on different networks.
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Sorry, I don't understand why it's impossible. Do you agree it's possible at least with 2 routers?
If not, I don't understand what's the purpose of lan with NAT if all lan must have strictly different subnet and address?You need to understand how a device knows whether to use a router or direct connection to another device. It is based on the IP address, the network address and the subnet mask. The network address is determined by doing a logical AND of the host address and subnet mask. This leaves only the network address. Then, when the device wants to send traffic to another, it again uses the subnet mask to determine whether the other device is on the same network or reachable through a router. If the other device has the same network address, it is assumed to be on the local network and the router, NAT or otherwise, will not be used. This means that it is impossible for anything from that device to ever reach the network on the other side of the router, since both sides have the same network address.
You'll have to advise your customer that what he wants is not possible. There's no way around it.
BTW, NAT was created to get around the IPv4 address shortage, though it's sometimes used to merge networks.
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where did he say he was using same address on both sides?
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where did he say he was using same address on both sides?
In the first post.
I have a configuration with 2 lan on 2 physical interfaces because my 2 lan have the same subnet and machines on LAN 1 and LAN 2 can have the same IP address.
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Agreed he can not do that with 1 pfsense. But he can do it with two - the picture he posted..
As long as the common wan network is different than 192.168.10 then he can attach multiple 192.168.10 devices to this common network via different nat boxes.. See attached example
