Questions tagged [tun]

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Unable to connect VPN client to OpenVPN server running Ubuntu 16.04.6

im a bit new to Linux and also rather stuck with this... any help here would be much appreciated... I am running Ubuntu 16.0.4 on my server and trying to connect a client to it but no luck. The ...
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Can not ping from tun->wlo1 and wlo1->tun

I have created a tun interface from a C program. Now I want to send tcp packets from this interface. But I got an error like No route to host on this step. Steps to reproduce:- Created tun ...
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OpenVPN: Cannot open TUN/TAP dev /dev/net/tun: Operation not permitted

I'm have some trouble with OpenVPN reccently, OpenVPN server are hosted on a VPS. It had been work for few months but last friday I reboot and update and upgrade since impossible to connect from my PC ...
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47 views

Embedding 3 bytes custom data in IPv4 header and then filter by iptables

In my modified OpenVPN server process, as an intermediate node, I'd need to embed my custom 3 bytes data in the header of every IP packet and then in the same machine (after going through tun) filter ...
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1answer
421 views

tun/tap works on incoming or outgoing packet?

When we create a tun virtual interface we use read and write to read and write packets from/into network stack. My question is when we use .read, we are actually reading outgoing packets (the packets ...
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1answer
105 views

what is difference between simple TUN and VPNs like PPTP and L2TP

In respect of VPNs and tunneling, as far as i know, TUN is a virtual interface works on network Layer 3 (IP packets), and is nothing more than a simple more likely UDP socket link in practice (I think)...
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240 views

socat tun device very low throughput

I was tinkering around with socat and tried to use socat for creating a TUN device for tunneling between two debian stretch servers. However, throughput seemed very low and comparing with iperf ...
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483 views

write into a tun interface and forward traffic to another computer

I have the following setup. An application on machine A creates an IP packet which is captured by the tun1 interface. I have added the route using the command : sudo route add -host 10.129.131.220 ...
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2answers
5k views

OpenVPN persist-tun option - what's the point?

According the OpenVPN 2 Cookbook: The persist-tun and persist-key options are used to ensure that the connection comes back up automatically if the underlying network is disrupted. These ...
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1answer
755 views

Multiqueue tun/tap interface

I am trying to understand how Multiqueue tuntap interface works. Following the instructions provided at: https://www.kernel.org/doc/Documentation/networking/tuntap.txt I was able to create multiple ...
2
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1answer
489 views

IPv6 on Linux tun/tap: NDP not working

I am working on an old code that used to connect different IPv6 devices over a different kind of network (a powe line netwrok, PLC, which is quite similar to 802.15.4). To do that, it created Linux ...
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1answer
3k views

OpenVPN TAP vs TUN in parallel

I have a few questions about our existing OpenVPN server setup and a requirement that we have to expand our access. Our current setup is as follows: 1 OpenVPN server (in TAP mode) Multiple VM ...
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1answer
758 views

How to set up single client TAP/TUN on the client for my OpenVPN?

My laptop OpenVPN client establishes a TAP device. My client config is TUN, though. This devices shows under ifconfig /ALL with the IP 10.8.0.6 and a subnetmask of 255.255.255.252. (!!!) This ...
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1answer
1k views

Can the inet address assigned to P-t-P tun interface be used for a client inet address if the server runs out of all addresses within a subnet?

I have an OpenVPN server with an Inet address 10.8.0.1 serving the subnet 10.8.0.0/24. I have two clients connected to this server and the status log (/etc/openvpn/openvpn-status.log)reads as follows: ...
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1answer
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Issues setting up TINC on Mac OSX 10.12.2

I have TINC setup on a few linux boxes and they are working great. linux001 (static ip vps - 10.0.0.1) macosx002 (connects to linux001 - 10.0.0.2) linux050 (connects to linux001 - 10.0.0.50) I also ...
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1answer
114 views

OpenVPN allows some users to jump to other hosts in the LAN

All users can connect to host where OpenVPN runs but some users can jump to other hosts in the LAN. For example, foo user can reach host 10.2.0.1/32 (where OpenVPN runs) and hosts at 10.0.0.0/24 but ...
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1answer
1k views

openvpn - Why do I have 2 tun interfaces on my server?

I have just configured watching this Hak5 video I found on Youtube. But what is bothering me is that why do I have two tun interfaces on my server ? Namely-: tun0 Link encap:UNSPEC HWaddr 00-...
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237 views

Why is my host not receiving packets sent across tun0?

I have a tun0 interface set up which allows packets to be sent as such: HOST (aaaa::1) ----> tun0 ----> SLIP ----> Router (aaaa::200:0:0:1) The router receives the packets, and can send back a ...
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1k views

How do I route traffic over the a tun0 device (IPSec VPN connection)?

I've set up an IPSec VPN tunnel between my laptop and work. The tunnel gets established, but routing does not. The relevant part of ifconfig is : eth0 Link encap:Ethernet HWaddr d4:be:d9:6f:a7:...
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1answer
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Endpoint to security gateway tunnel

I want to establish a connection between the client and the proxy server through a VPN tunnel in android device. I want to do this at layer 2 or 3 , where a packet can captured and encrypted. Please ...
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3answers
564 views

How do VPN servers/clients avoid routing their own remote connection packets through themself?

I am trying to conceptualise how networking works under the hood for linux VPNs which use TUN interfaces. My current best guess is as follows (please correct me): Connection established to remote ...
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0answers
622 views

Direct all traffic between Eth0:1 interface and VPN Tun0

If answered correctly this question will show you how to link a 2nd public IP address on a machine to a VPN server tunnel on that machine, so that the remote VPN client (running a server), sees this ...
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1answer
258 views

OpenVPN - connect server as client to itself

I have tried to setup a small openvpn network but I ran into one big problem. I have a server and a machine at home. So I created a openvpn server on my machine and a configured the client on the ...
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1answer
1k views

Prevent IP Spoofing on OpenVPN tun

I have a question regarding IP Spoofing and authentication. I have an OpenVPN server in TUN mode with many untrusted clients in the same VPN network, and I was wondering if one client is able to spoof ...
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1answer
745 views

/dev/net/tun exists, but OpenVPN is refussing to find it

I'm currently configuring an OpenVPN client on an arm microprocessor running debian squeeze, however I'm running into problems. As the below shows, /dev/net/tun exists: debarm:~# whoami root debarm:~...
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1answer
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How to create /dev/tun device inside unprivileged LXC container?

This question is similar to No tun device in lxc guest for openvpn . The LXC has evolved and the unprivileged LXC containers were introduced recently that offer another layer of security against ...
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1answer
5k views

What exactly happens to packets written to a TUN/TAP device?

I'm trying to send packets to an application listening on eth0 from machine's user-space as if they were coming from a remote machine. What I can't seem to find good documentation for is the exact ...
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OpenVPN tunnel not able to support secure connect request

In CentOS 7 host we have installed openvpn package and did create an tunnel using OpenVPN tunneling for eth9 and tap9. Everthing work fine for unsecure connection but when we try to connect to server ...
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2answers
990 views

Use OpenVPN tun device for specific request

I have setup an OpenVPN connection with the route-nopull configuration. So now no special routes have been added to the client's configuration and only a TUN device is created, like so: tun0 ...
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1answer
160 views

Setup openvpn as interface device only

I just setup OpenVPN client using this guide on The Geek Stuff But now (somewhat as expected) all my traffic is routed through the VPN. I actually just want to set up the interface device. Does ...
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2answers
3k views

OpenVPN Tunnel between two LANs, traffic dropped on the way?

I'd like to create a OpenVPN Tunnel between to LANs 192.168.1.0/24 and 192.168.2.0/24. However somehow packets entering the tunnel on one side don't come out of the other side ... The following ...
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2answers
4k views

openvpn connection has established but cant ping the server

I have a openvz vps and setup a openvpn server, and I successfully connect to the server in my ubuntu 14.10 client. server.conf: port 1199 proto udp dev tun ca ca.crt cert server.crt key server.key ...
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1answer
570 views

TCP RST from telnet/ssh daemons when connecting from openvpn

I have LAN_1 and LAN_2 interconnected with an openvpn tunnel terminated ona pair of SOHO routers running busybox. One of the vpn purpose is to allow clients on both LAN_1 and LAN_2, to administer the ...
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0answers
510 views

TUN/TAP VPN no internet connection

I have set up a tun/tap vpn to a VPS. For this, I created a 10/24 network and gave the server the IP 10.0.0.100 and my client got 10.0.0.200. I can now successfully ping the server / access my mail ...
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1answer
10k views

iptables: access connected openvpn client from the LAN with the VPN server

I have what is essentially a routing problem, and I'm not familiar enough with routing and iptables to effectively troubleshoot and set up my network needs. What's working I have an openVPN network ...
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1answer
4k views

How to make Tun module running at linux start

i installed Tun using: modprobe tun then did: lsmod | grep tun tun 83840 0 Please how to make Tun running at reboot? This is written on Hamachi website: ...Then add tun to ...
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1answer
729 views

Unbridged tap device

Good UTC evening! I've created a tap0 device on my host, it looks like: tap0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 inet 10.0.0.1 netmask 255.255.255.0 broadcast 10.0.0.255 ...
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1answer
517 views

bridge on openVPN client

I have some problem with setting up what i call a "remote entry point" (i'm sure ther is a real name for this) First things First : Here is my setup : ||==============================================...
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1answer
768 views

Is there a way to allow specific permissions to a non-root user?

I have a program that, at some point, create/destroys tun/tap virtual adapters. Obviously, for these specific operations this program requires root privileges. According to the program ...
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1answer
473 views

Where is the userspace used by TUN/TAP?

When I put data on a wire in qemu what sets the upper limit on the rate of data I can transmit? The situation is I set up two machines A and B create two tap interfaces openvpn --mktun --...
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1answer
3k views

Simple iptables port forwarding with masquerading not working

I'm trying to set up a simple VPN server on EC2 (Ubuntu 12.04) with the Android example ToyVpnServer. Its instructions: // There are several ways to play with this program. Here we just give an // ...
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2answers
11k views

openvpn: connection established, can't ping server tun interface (debian server, windows & os x clients)

My goal: I want to set up openVPN on a vServer from the company netcup, running Debian squeeze. I only want a VPN connection from client to server; clients should not be able to see each other, also ...
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2answers
5k views

How can I configure openvpn to proxy traffic only for processes that bind to the tun interface?

I'm trying to configure openvpn so that only traffic from certain processes goes over the vpn, but those processes could connect to anywhere. I'm trying to do that by having openvpn not do any route ...
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1answer
2k views

Why doesn't TUN device have BROADCAST flag?

When creating a TUN device in Linux, on my machine the created TUN device has following flags: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> Clearly MULTICAST is listed in there but not BROADCAST. ...
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1answer
3k views

How's the routing done in a very simple OpenVPN setup?

I've entirely configured (remotely) a Debian GNU/Linux dedicated server hosted in a professional capacity and I've got a network routing question (which AFAICT precisely fits the FAQ of serverfault). ...
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1answer
1k views

Forward IP packets to tunnel device

I have created an tunnel device using ip tuntap add dev tun0 mode tun user 0 group 0 I then assign it an ip address 192.168.0.1/22 ifconfig tun0 192.168.0.1 netmask 255.255.252.0 On my ethernet ...
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2answers
2k views

Forwarding traffic from TUN device (C++ backend) to the default gateway

The following problem is just a piece of the bigger solution I have a problem with. All other elements seem working so far, so I'll try to describe very small piece which I have problem with. I've ...
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1answer
2k views

Route packets from one VPN to another

I have two OpenVPN servers (10.8.0.0 and 10.9.0.0) set up on my OpenSUSE server. Within one network, each computer is visible to any other one, but I'd like to make it so that computers are visible ...
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3answers
23k views

How do I enable TUN/TAP forwarding?

I have a program which writes packets (destination address 10.3.0.2) to the TUN/TAP interface. Network: host1|tun0----eth1(10.3.0.1)|-------------------host2|eth1(10.3.0.2)| Wireshark captures ...
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8answers
2k views

opvnvpn: addressing nodes in LAN-behinds

I've setup an openvpn server which i can access remotely, once it is connected, it creates a tun0 device on both server and client with virtual ip 10.15.119.x. the openvpn server is itself 10.15.119.1....