I am building a home office network.
Due to physical limitation of my environment, I have setup my Wifi network under two routers in two different rooms.
DSL <------> Router 1 (Room 1) < ---- RJ45 192.168.1.105 --> Router 2 (Room 2)
Following is the current setting for bother Router
Router 1
IP: 192.168.1.1
DHCP Range: 192.168.1.0 - 192.168.1.255
Facilities connected:
DSL Wall point - Connected to internet (NBN).
Printer
Smart TV
Mobile
Other Desktop
Router 2
IP: 192.168.2.1
DHCP Range: 192.168.2.0 - 192.168.2.255
Facilities connected:
Laptop
Smart TV
Mobile
Gateway: 192.168.1.1
I can connect to internet from Router 2. However, I am not able to use Router 2 to access to the Smart TV and Printer that is connected to Router 1 .
Both routers does NOT support Access Point Mode. Therefore, they are connected Via RJ45 Ethernet.
Anyone have any idea on how to fix it?
Thanks in advance!
The problem is because that router uses NAT/NAPT for the lack of IP address and the protection of internal network. Normally, we use four types like Full Cone NAT, Restricted NAT, Port Restricted NAT and Symmetric NAT. They have different features, but they have a common feature: none of connection can be established from the outer side.
That means you can connect to outer side from inside, and then establish a connection, then the bidirection communication can work well. But if you firstly want to handshake from the outer side, it will fail.
So, here is something we called NAT traversal or NAT pounch hole to make some specifi internal IP/port can be connect from outside.
For your circumstances, the easiest way is to try upnp or nat-pmp if your router supports them. If not, it's relatively hard for you to simply connect them. Maybe you can try STUN/TURN/ICE, but I think you will not like them cause it's relatively hard.
Related
so the setup I've got:
Main Router which receives the internet connection and is my primary WIFI network: 192.168.1.0/24
Secondary Router which I've connected via the following method to create a separate LAN: 10.3.3.0/24. Main Router's LAN port --> Secondary Router's WAN port.
I've got this setup fine and can get internet from the Secondary Router's LAN, no problem.
My question is: Is it normal behavior to be able to ping a device connected to the main router from the secondary router?
I would like to isolate devices on each LAN so that devices connected to the separate LAN's can't communicate and wondering if I'm able to achieve this using 2 consumer grade routers?
Cheers!
This is normal behavior because the secondary router knows that IPs in the 192.168.1.0/24 subnet should be forwarded to its WAN port, so it can access hosts connected to that network.
Sadly, you usually can't create 2 segregated subnets with 2 consumer-grade routers, as these only have 2 network interfaces (one for WAN and one for the built-in switch).
I also do not recommend doing this, as double NAT can have unexpected side effects. If you really want to separate devices on your local network, looking into VLANs is a better way. You can use your existing router but will need a compatible switch.
If your routers support vlan management you should use separate vlans for both subnets. Otherwise you cant devide your networks.
I am a student learning computer network.
Here's how my network look like:
Router(NAT)
/ \
My PC My iPad
I have looked up my computer's routing table, and it shows the following:
$ netstat -r
Routing tables
Internet:
Destination Gateway Flags Netif Expire
default 172.22.128.1 UGScg en0
127.0.0.1 127.0.0.1 UH lo0
172.22.128.1 0:74:9c:96:72:55 UHLWIir en0 1200
172.22.161.13 ba:2e:b1:6f:69:39 UHLWI en0 740
I confirmed that the ip 172.22.161.13's gateway ba:2e:b1:6f:69:39 is the MAC address of my iPad.
I have a few doubts:
Shouldn't the routing table records ip address of next hop? how can it store a MAC address?
If the command netstat -r also lookups the arp table, how should it send packets to my iPad without going through the router?
The issue here is understanding the functionality of layer 2 and layer 3 in a network.
There is a difference between forwarding packets to the device located on the same subnet and on the device located on the different subnet.
I don't think there is a better definition of subnet, than devices that can communicate via a layer 2 protocol with each other. Routers are used to forward packets between devices in different subnets, that is, two devices in the same subnet do not communicate over the router, at least not over the "router" part of the router.
Devices that are located in the same subnet should be assigned the same IP prefix (i.e., the bits covered by network mask are the same). "Should" means that if it is not the case, then your network is configured wrong and may not work properly. This way your PC and your IPad can determine that they are on the same subnet and do not need to go over their default gateway.
Since your PC and your IPad are on the same subnet, they will talk to each other using layer 2. I am not sure from your configuration how many interfaces are actually wireless. If both interfaces are wireless, they may actually be capable of talking directly (i am not sure if wifi protocol in AP mode allows it, i think it does). If your PC is connected over Ethernet, then your Router also acts as a switch/bridge (which is layer 2 device) and forwards packets according to ethernet specification. You can learn about it by googling MAC learning.
This should answer the second question, now to the first one.
Actually, I wonder why the table is storing IP addresses. IP address of the next hop is not used in forwarding. First, note, that communication between devices which are two hops from layer 3 (i.e., routers) standpoint happens using layer 2. When a device makes routing decision, in takes the destination address from the IP header and looks up next hop, where what the device needs is a) outgoing interface b) how to reach next hop using layer 2 protocol of the interface. Then the device constructs an appropriate layer 2 header and sends the packet to the next hop device, which more or less does the same. So, actually your PC needs mac address of your router's interface to which it is connected to send the packet somewhere outside of the subnet.
Just in advance im sorry for my limited expertise with networking, i know the basics tho...
So the issue i have which i am hoping someone can shed some light on..
I want to have 2 routers, each with either own vlan, and i want one router to be able to talk the other but not vise versa,
So my Main router (192.168.1.1) is connected to the modem,
I want to get a second router and connect it to my main router,
The second router i want to have its own vlan (192.168.2.1)
Now that part is pretty easy, here is where i am in over my head
I want the computers on my Main router, to be able to access the ones on the second router... like ping, RDP, ETC
BUT - i dont want the computers on the second router to have access to the ones on the main router.....
Is this possible?
Thank you,
If you are using home routers the key is in the WAN interface.
All the hosts connected in the LAN ports can access the hosts in the WAN port, but not viceversa. Your border router act this way: if you want a hosts communicate directly from WAN to LAN you have to forward a port. For example, if you have DVR with cameras and you want to monitor them from Internet, you will have to forward the ports the DVR uses.
So, you could connect in the 192.168.2.1 subnet (just to clarify, this is not a VLAN, this is a subnet, or you can also call it just a net, VLANs are another thing) the PCs that you don´t want to be accessed from the other hosts.
VLANs are kind of partition of a LAN where the broadcast can propagate inside it but cannot go out. They are used for security, performance and easy of administration. They belong to the 2nd. layer of the OSI model.
The final topology in your case is as follows:
Let´s separate your computers in two groups: group A are the ones you don´t anyone has access and group B are the ones you want to be accessed from another PCs.
First you have your modem connected to the router that will act as border router. It´s LAN IP will be 192.168.1.1/24 (/24 is a notation for the subnet mask 255.255.255.0).
To that router you will connect to it´s LAN ports the group B PCs with IPs ranging from 192.168.1.2 to 192.168.1.254 (.0 is reserved, .1 is you border router and .255 is also reserved).
Also to that router you will connect the second router to its WAN port. In the second router you will set an static IP in its WAN port that belongs to the subnet of the border router. For example 192.168.1.2.
The second router LAN IP will be 192.168.2.1/24. Finally, you will connect the group A PCs to the second router LAN ports. With IPs from 192.168.2.2 to 192.168.2.254. This will be the more "protected" LAN.
I hope this could help!
In my current network setup, I have a Cisco RVS4000 router that feeds into a 48 port ethernet switch and a Ubiquiti PicoStation M2 wireless access point.
I want the Cisco router to act as a DHCP server for the whole network. I am unsure how I should setup the Ubiquiti PicoStation M2...
The 2 options which seem relevant are Network Mode and Wireless Mode.
The options for Network Mode are:
Bridge
Router
SOHO Router
The options for Wireless Mode are:
Station
Station WDS
Access Point
Access Point WDS
From what I've read and what I want... I'd go for Bridge and Access Point?
Yes, Bridge and Access Point are the correct settings for extending your existing network onto wireless "media". the other options would create a second network.
The easiest way:
Connection in this order: Router -> Switch -> PicoStation
Set the PicoStation in "Access Point" Mode.
If you do it this way the clients that connect the Access Point (PicoStation) will retrieve an DHCP Adresse from the Router. The wireless clients are in the same subnet as the clients connected to the switch.
If you want to divide the "normal" clients from the wireless clients you set the PicoStation to Router Mode.
Access Point transmission media wireless, antena.
Bridge if transmission media like cable
the recommended option is router if you set DHCP
but in wireless i'm not sure about best option
I am trying to achieve double NAT working with UPNP. My PC connection is as follows:
Internet -> Router 1 -> Router 2-> PC
I have successfully done port forwarding on the Router 2, but not able to do on router 1. Due to which packets from the server(which is on Internet) are not able to reach PC.
Gone through few document how to tackle but mostly found manual way like bridge the network or put the lan wire.
I am rather looking for the some recursive solution using UPNP protocol to do the port forward on both routers. I guess torrent, skype does the same.
How to get the network interface related to router 1 and then port forward on that Network ?
Any help would be highly appreciated.
Thanks,
Pawan
There is an IGD-PCP IWF specification that tries to solve similar problem, although it assumes PCP support on your "Router 1", not UPnP. So let's try to approach this issue from a pure theoretical point of view with two plain UPnP routers/NAT devices.
There are several distinct steps of UPnP communication as per UPnP Device Architecture version 2.0:
addressing
discovery
description
control
eventing
presentation
Addressing is of little interest for us, let's assume proper DHCP everywhere and be done with it. Eventing and presentation are also almost useless in our case. So the main things to be concerned about are discovery, description and control.
Discovery works via SSDP message exchange. SSDP uses UDP for its transport with port number 1900 (by default) and well-known multicast address.
Description starts with URL provided by the device at discovery phase, the control point (that is PC in our case) needs to issue an HTTP GET request on this URL and that means it uses TCP as a transport protocol with devices IP address (unicast).
Control starts with URL provided by the device in its description, and it uses SOAP on top of HTTP on top of TCP which in turn also means unicast IP for us.
So, what all of that means for double NAT is that in description and control steps of UPnP interaction we have zero problems communicating from PC to Router 1 as all of that is just standard TCP with unicast IP addresses. But to get to the description step we need to have a URL of Router 1, so let's take a closer look at how this URL is acquired the normal way.
There are two main mechanisms for discovery — advertising (when the device periodically multicasts some information about it) and search (when the control point sends multicast search message and the device answers to that with unicast response). Obviously, by default our PC behind the Router 2 can't get multicast advertisements from Router 1 and the Router 1 can't get multicast search messages from PC, so we have a problem here and the question now is whether there is a possibility for communication without multicast.
Luckily, the same architecture document says:
In addition, a control point is allowed to unicast a discovery message to a specific IP address on port 1900 or on the port specified by the optional SEARCHPORT.UPNP.ORG header field (which supersedes port 1900 for this use), searching for a UPnP device or service at that specific IP address.
...
All devices shall listen to incoming unicast search messages on port 1900 or, if provided, the port number specified in the SEARCHPORT.UPNP.ORG header field and shall respond if any of their root devices, embedded devices or services matches the search criteria in the discovery message.
And this means that if you know the Router 1 IP address (from Router 2 side, of course), you can (and most importantly, allowed by specification to) communicate with it with unicast UDP messages and that is also NAT-friendly, so not an issue to be done from PC behind the Router 2.
The only thing left is getting Router 1 IP address. Unfortunately, there is no easy standard way to do that, but you have at least two options: tracerouting (in whatever fashion you want) and brute force IP scanning (most probably, the potential set of IPs for Router 1 is limited).
Now you can communicate with the Router 1, but there is still one minor thing you should always remember while communicating with it — in any internal UPnP messages you should use Router 2 IP address (as seen from Router 1 side) and its ports. Like in NewInternalClient parameter of AddPortMapping action on Router 1 you should use Router 2 IP. This, BTW, raises a question of Router 2 IP, but you can get that via Router 2 UPnP ExternalIPAddress variable of WANIPConnection service (this service is required for IGDs to implement).
So, to summarize:
this technically can be done, although I doubt that any standard library would do that for you
two things you need are:
Router 2 "external" IP and you get that via ExternalIPAddress variable of WANIPConnection UPnP service
Router 1 "internal" IP (from Router 2 side), that requires tracerouting or scanning
given Router 1 IP you just need to use unicast messaging at discovery step instead of multicast
everything else should just work, with only caveat of using Router 2 "external" IP instead of PCs IP in the UPnP messages
With the upnpc cli tool I've been able to get Double NAT port forwarding working.
For my example, let's say I want port 6667 to be forwarded to my machine, 192.168.50.123, behind a double NAT. The first layer of NAT has the IP range 192.168.1.1-255, and then 2nd layer has IP range 192.168.50.1-255.
On a machine inside the 2nd layer of NAT, just setup port forwarding with upnpc like normal.
$ upnpc -a 192.168.50.123 6667 6667 tcp
...
$ upnpc -l # this will confirm the rule is in place
...
Now for the slightly tricky part. I now issue UPNP requests to the outer layer NAT. Since the usual SSDP discovery won't work, I have to specify the XML root description URL manually. It's often something standard like http://192.168.1.1:5000/rootDesc.xml, though on some hardware the port number is randomized. I find just port scanning the gateway address will eventually reveal it.
Now that I have the rootDesc url, http://192.168.1.1:5000/rootDesc.xml, I then issue UPNP command to the outer layer NAT:
$ upnpc -u "http://192.168.1.1:5000/rootDesc.xml" -a 192.168.1.XX 6667 6667 tcp
...
$ upnpc -u "http://192.168.1.1:5000/rootDesc.xml" -l # this will confirm the rule is in place
...
With the -u option instead of discoverying the rootDesc, it just uses the URL provided.
The address 192.168.1.XX should be the 2nd layer network's IP address on as seen by the 1st network. When running the first set of UPNP commands this will be shown since it's the "external" address from that NAT's perspective.
With that now setup, traffic will go like this:
<INTERNET> --> MY_PUBLIC_IP -> 192.168.1.XX -> 192.168.50.123