Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [openvpn]

OpenVPN is a free and open source software VPN solution. It allows secure point-to-point or site-to-site connections with routed or bridged configurations and remote access facilities.

82
votes
10answers
160k views

Should I use tap or tun for openvpn?

What are the differences between using dev tap and dev tun for openvpn? I know the different modes cannot inter-operate. What is the technical differences, other then just layer 2 vs 3 operation. ...
75
votes
7answers
115k views

OpenVPN vs. IPsec - Pros and cons, what to use?

Interestingly I have not found any good search results when searching for "OpenVPN vs IPsec". So here's my question: I need to set up a private LAN over an untrusted network. And as far as I know, ...
66
votes
2answers
79k views

Getting “Cannot ioctl TUNSETIFF tun: Operation not permitted” when trying to connect to OpenVPN

I'm trying to setup an OpenVPN Access Server in AWS using the market place AMI, but I;m struggling to connect to it. The access server is up and running. I've also added a user with Auto-Login and ...
51
votes
5answers
137k views

How to view connected users to open vpn server?

I'm developing a website for managing OpenVPN users with Django framework. But I need to know is there any way to extract active users from OpenVPN? My server is running Ubuntu 12.04.
39
votes
6answers
79k views

How to check that an OpenVPN server is listening on a remote port without using OpenVPN client?

I need to check that an OpenVPN (UDP) server is up and accessible on a given host:port. I only have a plain Windows XP computer with no OpenVPN client (and no chance to install it) and no keys needed ...
39
votes
3answers
101k views

How to ensure OpenVPN connection uses specific DNS?

I'm using OpenVPN through Tunnelblick on MacOS X Lion. I need to set specific DNS (with local IP, which works only when VPN is up) for the duration of this VPN session only. I do not have access to ...
37
votes
4answers
128k views

Generate an OpenVPN profile for client user to import

Is there any documentation or resource describing how to generate and host a profile for an OpenVPN client to import? Ideally would like my users to not have to separately fetch a .zip file of the ....
37
votes
6answers
52k views

How do you avoid network conflict with VPN internal networks?

While there's a wide variety of private non-routable networks across 192.168/16 or even 10/8, sometimes in being thoughtful of potential conflict, it still occurs. For example, I set up an ...
32
votes
2answers
34k views

Can generated OpenVPN keys be used on multiple clients?

We are experimenting with running an OpenVPN server for our business. One question I can't seem to find the answer to is this: When we generate keys for one of our users for them to use at home, can ...
31
votes
4answers
38k views

OpenVPN performance: how many concurrent clients are possible?

I am evaluating a system for a client where many OpenVPN clients connect to a OpenVPN server. "Many" means 50000 - 1000000. Why do I do that? The clients are distributed embedded systems, each ...
26
votes
3answers
50k views

telnet counterpart for UDP

Is there anything that enables a "telnet-like" functionality for UDP? I know the difference between TCP and UDP, and why telnet itself won't work - but I'm wondering if there is something similar to ...
25
votes
5answers
35k views

Very low TCP OpenVPN throughput (100Mbit port, low CPU utilization)

I am experiencing extremely slow OpenVPN transfer rates between two servers. For this question, I'll call the servers Server A and Server B. Both Server A and Server B are running CentOS 6.6. Both ...
24
votes
4answers
161k views

How to push my own DNS server to OpenVPN?

I have defined an unbound DNS server on my VPS and it appears to work. I need to use the DNS server instead of public DNS servers because some ISPs have blocked public DNS IPs. My openvpn.conf file is:...
24
votes
1answer
52k views

Can someone please explain easyrsa vars options for PKI generation

I am using OpenVPN and whilst I can generate certificates using easyrsa just fine I don't really understand the settings in the easyrsa vars file: export KEY_COUNTRY="" export KEY_PROVINCE="" export ...
22
votes
2answers
14k views

Comments in OpenVPN client config files?

Is it possible to put comments in the client config files (those in the path specified by "client-config-dir") for OpenVPN, i.e. something beginning with "#" or "//" or the like? If so, what is the ...
21
votes
3answers
39k views

Why is `--duplicate-cn` not recommended in OpenVPN?

Is this for security reason, or performance reason?
21
votes
3answers
55k views

How to connect multiple VPNs using OpenVPN on Windows 7 on the same time?

I work most of the time remotly from home. To gain access to the different servers (via SSH) I have to use OpenVPN. I would like to connect to all of them (three, sometimes four) at once, so I dont ...
21
votes
4answers
40k views

Is there a real way to connect to WatchGuard's VPN from Linux?

WatchGuard officially has clients only for Windows and Mac. But I see that it uses openvpn internally. I couldn't connect to WG from Linux. Is there someone who actually get this working? How?
21
votes
2answers
15k views

SSH tunneling is faster than OpenVPN, could it be?

Logically, VPN should be faster than SSH for tunneling, because: It's running on UDP and not TCP (so no TCP over TCP) It has compression However, today I tested Redis replication over both methods. ...
20
votes
7answers
36k views

NetworkManager is not changing /etc/resolv.conf after openvpn dns push

I've got a problem which is "NetworkManager is not updating /etc/resolv.conf after openvpn connection with dns push configured". Here's my openvpn server config: (I've changed domain name to ABC.COM ...
20
votes
5answers
22k views

Connect an iPhone to OpenVPN

Is there a way to connect an iPhone to our company OpenVPN server?
18
votes
1answer
99k views

OpenVPN not default gateway for all traffic

I'm trying to make my client forward all traffic through a VPS running OpenVPN. As you can see, it will allow pings to both domains and raw IP addresses, but it will not allow traffic like that made ...
18
votes
4answers
22k views

How do I prevent TCP connection freezes over an OpenVPN network?

New details added at the end of this question; it's possible that I'm zeroing in on the cause. I have a UDP OpenVPN-based VPN set up in tap mode (I need tap because I need the VPN to pass multicast ...
17
votes
7answers
74k views

how to auto start openvpn (client) on ubuntu 12.04 cli?

I have an *.ovpn file that works if I type in sudo openvpn client.ovpn Now I would like to start up openvpn when I boot the computer. It's a headless version of ubuntu - if that matters - 12.04 ...
17
votes
3answers
19k views

No tun device in lxc guest for openvpn

I am trying to set up an openvpn server inside a lxc guest. However, it seams there is no tun device available in the container. Starting openvpn inside the container gives me this error: Tue Sep 18 ...
17
votes
1answer
14k views

Why Openvpn use network 0.0.0.0 netmask 128.0.0.0 as default route?

If you use "redirect-gateway def1" option in openvpn config file,the server will add a default gateway on your route table, what i want to konw is Why openvpn did not use network 0.0.0.0 netmask 0.0....
17
votes
3answers
39k views

OpenVPN and DNS. How to?

I'm using OpenVPN to set up a VPN to connect my laptop at home to my workplace LAN. I want to be able to refer my workplace computers by their name and not by their IP but I can't. This is my ...
16
votes
10answers
26k views

OpenVPN easy-rsa build-key automation?

I have a lot of keys to generate for my clients VPN server. Whenever I use easy-rsa to generate the keys like this: ./build-key client1 There is some output with a series of questions. The questions ...
16
votes
6answers
146k views

Fix 'TLS Error: TLS handshake failed' on OpenVPN client

I am configuring OpenVPN 2.3.6-1 on my Arch Linux server in order to encrypt SMB traffic over the public Internet. When I test the setup on one of my Linux virtual machine clients, I get the error: ...
15
votes
3answers
72k views

Unable to logon to vpn [closed]

My openvpn client log file- The interesting bit: Tue Oct 26 12:32:49 2010 TLS Error: cannot locate HMAC in incoming packet from 67.228.223.12:3389 Tue Oct 26 12:32:49 2010 Fatal TLS error (...
15
votes
5answers
22k views

OpenVPN make redirect-gateway optional

I'm currently running an OpenVPN server for multiple clients. All traffic is directed through the VPN (it's set up as gateway; push "redirect-gateway def1"). So far, all is working fine. However, I'...
14
votes
2answers
14k views

OpenVPN: How to mitigate path MTU issues on a per-client basis?

We have dozens of embedded devices installed at customers, all calling home to our OpenVPN service. That works fine in general, but a few of our customers have severe path MTU issues. Our influence on ...
13
votes
7answers
26k views

VPN server on Google Compute Engine with OpenVPN

I'm trying to use Google Compute Engine server as VPN server for all my traffic (I'm living in Russia, we have some issues with censorship here). There is mini-tutorial about VPN on GCE, but it's ...
13
votes
1answer
3k views

OpenVPN low performance. Do I have MTU problems? Dumps inside

I have problems with an OpenVPN tunnel which does not reach line speed. The gateway is a Debian Jessy virtual server hosted at OVH. The client is either my freebsd 10.2 homeserver (Intel I3 Ivy Bridge)...
12
votes
4answers
4k views

Can a shell script wait for a file to change and take action?

I wonder if I can write a script that will monitor for a change in a file and execute some action when the change is detected. Detailed explanation: OpenVPN writes its status to a file every 1 ...
12
votes
2answers
15k views

How can multiple clients of an openvpn server find each other?

I am bringing up an openvpn server that will support multiple clients into a private subnet. So on the private subnet the clients connecting will get IP addresses such as 10.8.0.10, 10.8.0.11, etc. ...
12
votes
5answers
11k views

SSH traffic over openvpn connection freezes when I cat a file

I have an openvpn (version 2.1_rc15 at both ends) connection setup between two gentoo boxes using shared keys. it works fine for the most part. I use mysql, http, ftp, scp over the vpn with no ...
12
votes
3answers
7k views

Are there any Distributed/mesh-like/P2P VPNs?

I have my personal VPN, connecting several devices so they can have fixed IP addresses on an always-reachable network (as long as they are connected to the Internet). This is necessary for me, since ...
12
votes
4answers
10k views

Prevent SSH connection lost after logging into VPN on server machine

I encountered an issue that I can't deal with. When I'm logged onto an VPS over SSH and try to estabilish VPN connection on that VPS, the SSH connection between VPS and my machine get lost. I assume ...
12
votes
2answers
9k views

Is there any solution to make OpenVPN authentication with Google ID?

Or, maybe any oauth? All I could find - is 2factor authentication with google. But I'd like to use Google Apps base for OpenVPN auth. I believe that it is possible to make something like gitlab. ...
11
votes
2answers
2k views

OpenVPN unable to disable encryption

Both in server and client config I have set: cipher none auth none Following this advice I am also using UDP port 1195. When I launch server and client I get following warnings: Tue Dec 4 12:58:...
11
votes
6answers
25k views

Allowing SSH on a server with an active OpenVPN client

I have a VPS running CentOS 7 that I connect to with SSH. I would like to run an OpenVPN client on the VPS so that internet traffic is routed through the VPN, but still allow me to connect to the ...
11
votes
7answers
73k views

OpenVPN issue - TLS key negotiation failed to occur within 60 seconds

I'm configuring an OpenVPN (version 2.3.10) server on a Windows 2012 server but I cannot make it to work. The server is behind a router and I opened the 1194 port and created a rule to forward ...
11
votes
2answers
17k views

stunnel vpn traffic and ensure it looks like SSL traffic on port 443

I am trying to make my outgoing and incoming traffic look as legitimate as close to SSL traffic as possible. Is there a way to DPI my own traffic to ensure it looks like SSL traffic and not OpenVPN ...
11
votes
4answers
38k views

How do I improve OpenVPN reliability over a high latency link?

We are running a OpenVPN VPN over a BGAN satellite link where ping times are about 3 seconds. We use it in a tun configuration, and we're running on Linux (CentOS). It is primarily email that will be ...
10
votes
4answers
42k views

openVPN disconnect via command line in linux

Is there a way to disconnect an openvpn connection that was established by free-radius with a shell command line? I have all information about the openvpn connection: Username Client IP ...
10
votes
1answer
60k views

VPN: ERROR: Linux route add command failed

I have configured a VPN server local 192.168.0.250 dev tun proto udp port 1194 ca /etc/openvpn/easy-rsa/keys/ca.crt cert /etc/openvpn/easy-rsa/keys/server-vpn.crt key /etc/openvpn/easy-rsa/keys/...
10
votes
2answers
389 views

Traffic routing with unreliable connections

I have a group of offices that are all connected to the main office via DSL links on the far end to save costs. (We're a non-profit, don't ask) We've historically had noticeable problems with the ...
10
votes
1answer
7k views

How to enable 2-factor auth using Google Authenticator for .ovpn file based openVPN access?

I have an openVPN setup where the users do not have shell accounts on the Debian VM running openVPN. The articles I found while Googling all have instructions of setting up Google Authenticator for a ...
10
votes
3answers
5k views

Changing Windows Network Profile from “DomainAuthenticated” to Public

I have a domain joined Windows Server 2012 R2 box that has the OpenVPN 2.3.13 client software installed on it. When the VPN connection is active the "Ethernet 2" (TAP interface) connection is placed ...