I Have a Macbook that connects to two networks. One by ethernet port and the other by a usb ethernet adapter. I'm looking to forward an incoming call to a specific port on the macbook to a different ip/port on the other network. Is this possible?
So for instance, i would like a call to 192.168.178.20 port 7000 to be forwarded to 192.168.10.20 port 8000.
Thanks in advance!
Not my strong suit, but as no-one is answering you, I'll suggest this...
You should be able to get there with ssh something like this:
ssh -L 192.168.178.20:7000:192.168.10.20:8000
I think you will need to go to Apple->System Preferences->Sharing and enable the Remote Login service first.
Related
I've created a simple client/server program with the help of winsock in vb6. It perfectly works on LAN but the problem is it doesn't work on WAN. All ports are already open, Firewall is already Off, I have dynamic IP so I used No-ip to get named IP address.
One more think I want to ask is , is it important to open port on both client and server? For eg- I've created the program on port 50505 and on the client computer the port is open but is it important to open 50505 on server also??
Here is my project.
If anyone could find the problem please let me know. I would appreciate a lot
Okay, first make sure that in the client side program that the Localport is not set to anything because Windows will assign it one, but the RemotePort is set to 50505. On the server side, the RemotePort is set to nothing, and the LocalPort is set to 50505.
Next you need to make sure your server has a static IP on your network.
So if your router's LAN IP is 192.168.1.1 you need to set your server's to
something like 192.168.1.50, just make sure that it doesn't get put in the range or the
DHCP server (That's the server that gives each computer a IP address from the router).
Next you need to setup your router for "Port forwarding". Be default your router had no idea what to do with data that the internet sends to it. You have to setup the router to forward any data from port 50505 to your server on your network.
While this seams really long and drawn out, it shouldn't take more than 5-10 min's to setup.
Good luck!
You need to configure the router that the server is behind to forward connections on that port to the computer running the server.
Otherwise, the client will not be able to connect to the server.
This is part programming, part sysadmin, so please excuse me if you feel that this should be over on serverfault.
I have an application that is not SOCKS aware and that we need to use through a firewall. We cannot modify the application to have SOCKS support either.
At the moment, we do this by aliasing the IPs the application talks to the loopback adapter on the host, then creating SSH tunnels out to another host. The IP's the application uses are hardcoded. Our SSH connections look like:
ssh -L 1.2.3.4:9999:1.2.3.4:9999 user#somehost
Where 1.2.3.x are aliases on the loopback.
So the application connects to the open port on the loopback, which gets sent out to the SSH host and onto the real 1.2.3.4.
It works, but the problem is that this application connects to quite a few IPs ( 50+ ), so we end up with 50 ssh connections out from the box.
We've tried to use several 'proxifying' apps, like tsocks and others but have had alot of issues with them ( the app is running on OS X and tsocks doesn't work so well, even with the patches )
Our idea was to write a daemon that listened on all interfaces on the specified port - it would then take the incoming packets from the application, scrape the packet info ( dst IP, port, payload ), recreate the packet and proxify it through a single SSH SOCKS connection ( ssh -D 1080 user#somehost ). That way, we only have 1 SSH connection that all the ports are being proxied through.
My question is - is this feasible? Is there something that I'm missing here? I've been combing through pfctl, ipfw, iptables docs, but I don't see any option to do it through those and this doesn't seem like it'd be the most difficult thing to code. It would recreate the packet based on the original destination IP and port, connect to the local SOCKs proxy and resend the packet as if it were the original application, but now with SOCKS support.
If I'm missing something that someone knows about that already does this, please let me know. I don't know socket programming or SOCKs too well, but this doesn't seem like it'd be too big of a project to tackle, but I'd like some opinions if I'm biting off way more that I should.
Thanks
If your application could add SOCKS client support, you can simply ssh -D lock_socks_port remote_machine, which will open up the local *lock_socks_port* as a SOCKS server at localhost, which can then connect to any host accesible by the remote machine.
Example: imagine you are using an untrusted wifi network without encryption. You can simply launch ssh -D 1082 home, and then configure your web browser to use localhost:1080 as SOCKS server. Of course, you need a SOCKS-enabled client. All the traffic would appear as coming from your gateway, and the connection would be opaque to those snooping the wifi.
You can also open a single ssh client with an indefinite number of LocalForward requests, which would be tunneled on top of a single ssh session.
Moreover, you can add ssh connections to an already-established ssh connection by using the ControlMaster and ControlPath options of ssh.
Is there a way to find out the IP address of a device that is directly connected to a specific ethernet interface? I.e. given one host, one wired ethernet connection and one second host connected to this wired connection, which layer or protocol below IP could be used to find this out.
I would also be comfortable with a Windows-only solution using some Windows-API function or callback.
(I know that the real way to do this would probably via DHCP, but this is about discovering a legacy device.)
Mmh ... there are many ways.
I answer another network discovery question, and I write a little getting started.
Some tcpip stacks reply to icmp broadcasts.
So you can try a PING to your network broadcast address.
For example, you have ip 192.168.1.1 and subnet 255.255.255.0
ping 192.168.1.255
stop the ping after 5 seconds
watch the devices replies : arp -a
Note : on step 3. you get the lists of the MAC-to-IP cached entries, so there are also the hosts in your subnet you exchange data to in the last minutes, even if they don't reply to icmp_get.
Note (2) : now I am on linux. I am not sure, but it can be windows doesn't reply to icm_get via broadcast.
Is it the only one device attached to your pc ?
Is it a router or another simple pc ?
To use DHCP, you'd have to run a DHCP server on the primary and a client on the secondary; the primary could then query the server to find out what address it handed out. Probably overkill.
I can't help you with Windows directly. On Unix, the "arp" command will tell you what IP addresses are known to be attached to the local ethernet segment. Windows will have this same information (since it's a core part of the IP/Ethernet interface) but I don't know how you get at it.
Of course, the networking stack will only know about the other host if it has previously seen traffic from it. You may have to first send a broadcast packet on the interface to elicit some sort of response and thus populate the local ARP table.
Windows 7 has the arp command within it.
arp -a should show you the static and dynamic type interfaces connected to your system.
Your Best Approach is to install Wireshark, reboot the device wait for the TCP/UDP stream , broadcasts will announce the IP address for both Ethernet ports
This is especially useful when the device connected does not have DHCP Client enabled, then you can go from there.
You can also get information from directly connected networking devices, such as network switches with LDWin, a portable and free Windows program published on github:
http://www.sysadmit.com/2016/11/windows-como-saber-la-ip-del-switch-al-que-estoy-conectado.html
LDWin supports the following methods of link discovery: CDP (Cisco Discovery Protocol) and LLDP (Link Layer Discovery Protocol).
You can obtain the model, management IP, VLAN identifier, Port identifier, firmware version, etc.
I'd like to sell headless Linux servers to SOHO users. Typically, they'll have a DHCP-capable ADSL modem cum switch to which they'll connect their workstation and the server.
In order to just show up with the server, I need to find a way to just plug the server into the switch to get an IP address from the modem, and then have the server broadcast its adresse so I can then connect to it with Putty from the workstation.
I thought about using Samba to broadcast a message using the Messenger Service, but unless I'm mistaken, this only works if the two hots are configured to use the same workgroup/domain.
Do you know of way to get the server's IP address from the workstation?
Thank you for any tip.
Take a look at UPnP and zeroconf services like Apple's Bonjour.
I'd probably suggest using the normal approach for switches and modems as you are treating your device as an appliance, i.e. set a default IP 192.168.0.1, and connect to that to then configure the device into the local infrastructure.
I don't know of any good solutions.
Some DHCP servers will register the name you send in the request - then give that name in your setup instructions. But I suspect home user DSL routers aren't in that category.
Maybe you could ship a tool on CD that does arp requests to get the IP address? (Given the MAC address printed on the box)
Broadcast packets periodically on some arbitrarily chosen UDP port, and build some client software to listen for those packets.
Is there a Mac/Unix commands that lets you see the local network in terms of machines/IP addresses? If there's something on the Mac that is gui-based that would be great too.
ping the broadcast address (the broadcast address is printed as part of the output to ifconfig en0)
The hosts answering are on your local network. (You may also try arp -a but that only keeps track of recently contacted hosts so you may want to run it after the broadcast.)
There is a program called Bonjour Browser that will list well known services that have registered on your local network. I believe that most Macs have one or more registered protocols by default.
The only way to reliably do this is to scan the network using ping sweeps and similar techniques looking for open ports etc on various addresses. You can do that with nmap which is available for OS X. See http://www.netadmintools.com/art406.html for an example.
EDIT: Just to clarify, as diciu pointed out, you can usually ping the broadcast address and/or use your arp cache as well. This will probably work for most home networks where directed broadcast is allowed.
If not, then you would need to run a ping sweep with a tool like nmap to individually check each address for an available host. Many network discovery/scanning tools can check for more than just ping, looking for listening ports, SNMP, etc. as well.
in the days of tiger (10.4) every mac broadcast a 'presence' service on bonjour, which made finding macintoshes on the network a snap. alas, no more...
You can use netdiscover on Mac OS, which is based on ARP packets. It will send ARP requests and scan the response.
For example, run netdiscover command sudo netdiscover -i en0 -r 10.106.0.0/16 in my local network would bring the following result:
Try IP Scanner 2.5 for OS X. http://10base-t.com/ Looking for others, but that's the only real one I've found for OS X.
You can use Nmap but that seems to be a bit much for your stated goals.
OS X ships with netstat, or open Up /Applications/Utilities/Network Utility.app, perhaps this will work for you?
EDIT: oops. netstat doesn't do what I thought.
angry IP scanner for a no mus - no fuss IP scanner with basic port scanning.
NMap and Zenmap for the big power scans.
I actually use both together, as nmap can get easily sidetracked by certain reverse proxy boxes.