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WARNING: this guide assumes that you have no IPv6 connectivity. If you have, you should block outgoing IPv6 packets while connected to the VPN with "ip6tables". Please see https://airvpn.org/faq/software_lock Here is a guide to prevent leaks and completely stop traffic when the VPN drops in Linux. If the openvpn connection drops you will not be able to access the internet while the firewall is activated. Just click the "stop firewall" button and reconnect with Openvpn, then re-enable to firewall. If you wish to connect to the internet without openvpn just press the "stop firewall" button within firestarter. This way you are protected in the VPN drops. Tested on Debian, Ubuntu, Mint, and OpenSUSE. This is assuming you have already setup OpenVPN on Linux after following the guide here-----> https://airvpn.org/linux/ 1). Install Firestarter firewall for Linux by opening the terminal and typiing ----> sudo apt-get install firestarter 2). Allow traffic on the OpenVPN interface by updating /etc/firestarter/user-pre. There are multiple ways to do this depending on your Linux Distro. Here are 2 examples. A). Open the terminal with root privileges and type-----> gksu gedit /etc/firestarter/user-pre Add the following text to /etc/firestarter/user-pre and save----------> $IPT -A INPUT -i tun+ -j ACCEPT $IPT -A OUTPUT -o tun+ -j ACCEPT . The second way is simply to go to the folder /etc/firestarter/ and click on the file USER-PRE and open in terminal with root privileges. Then add the code and save-----> $IPT -A INPUT -i tun+ -j ACCEPT $IPT -A OUTPUT -o tun+ -j ACCEPT 3). Restart Firestarter by opening the terminal and typing ------------> sudo /etc/init.d/firestarter restart 4). Follow the images below to finish. You may have to restart the machine afterwards. <a href="/external_link/?url=http%3A%2F%2Fbeta.photobucket.com%2F" target="_blank"><img src="/external_image/?url=http%3A%2F%2Fi1285.photobucket.com%2Falbums%2Fa582%2Fcorsair28%2F01firewallwizard.png" border="0" alt="Photobucket"/></a> <a href="/external_link/?url=http%3A%2F%2Fbeta.photobucket.com%2F" target="_blank"><img src="/external_image/?url=http%3A%2F%2Fi1285.photobucket.com%2Falbums%2Fa582%2Fcorsair28%2F02firewallwizard.png" border="0" alt="Photobucket"/></a> <a href="/external_link/?url=http%3A%2F%2Fbeta.photobucket.com%2F" target="_blank"><img src="/external_image/?url=http%3A%2F%2Fi1285.photobucket.com%2Falbums%2Fa582%2Fcorsair28%2F03wizard.png" border="0" alt="Photobucket"/></a> <a href="/external_link/?url=http%3A%2F%2Fbeta.photobucket.com%2F" target="_blank"><img src="/external_image/?url=http%3A%2F%2Fi1285.photobucket.com%2Falbums%2Fa582%2Fcorsair28%2F04selectthepolicytab.png" border="0" alt="Photobucket"/></a> <a href="/external_link/?url=http%3A%2F%2Fbeta.photobucket.com%2F" target="_blank"><img src="/external_image/?url=http%3A%2F%2Fi1285.photobucket.com%2Falbums%2Fa582%2Fcorsair28%2F05nothingdotooninboundp.png" border="0" alt="Photobucket"/></a> <a href="/external_link/?url=http%3A%2F%2Fbeta.photobucket.com%2F" target="_blank"><img src="/external_image/?url=http%3A%2F%2Fi1285.photobucket.com%2Falbums%2Fa582%2Fcorsair28%2F06selectoutboundtraffic.png" border="0" alt="Photobucket"/></a> <a href="/external_link/?url=http%3A%2F%2Fbeta.photobucket.com%2F" target="_blank"><img src="/external_image/?url=http%3A%2F%2Fi1285.photobucket.com%2Falbums%2Fa582%2Fcorsair28%2F07policyoutboundsetrest.png" border="0" alt="Photobucket"/></a>

Personally I'm using gufw for linux, and it works very well. However, it's important to remember that gufw is just a graphical frontend for ufw, and ufw, in turn, is just a friendlier system for manipulating IPTABLES (which is again a system for manipulating netfilter directly in the running kernel). Gufw is perhaps over simplified, which is why I find it not really that great for anything else than providing an overview of your rules and turning the firewall on an off. With regards to firestarter, I have tried it once, but I didn't really have any good experience with it, since, as you guys have already posted, it seems rather poorly coded and does some odd things when manipulating IPTABLES. What I found invaluable about ufw is its ability to specify rules based on interface and its simplictity even though its quite powerful. This was my main motivation for using it over other solutions like Firestarter, and Shorewall was too complicated for my taste. My rule approach goes like this: Allow connections OUT to AirVPN servers I use the most (for connecting/reconnecting to the AirVPN service, entry IP's, marked RED on the screenshot) Allow connections OUT FROM the tun0 interface TO anywhere (when I'm connected, this is the interface used to communicate to the Internet, marked GREEN on the screenshot) Allow connections (UDP/TCP) IN TO the tun0 interface to a specific port (to enable AirVPN's port forwarding feature, marked BLUE on the screeshot) Allow connections IN FROM the 192.168.1.0/24 network TO the eth0 interface (enable home networking. Notice how it's on a different interface, YELLOW) Allow connections OUT FROM the eth0 interface TO the 192.168.1.0/24 network (enable home networking, also on the eth0 interface, YELLOW) Block ALL other traffic (by choosing DENY/DENY in gufw) When the VPN drops (and the tun0 interface is disabled), the only connections allowed OUT from the computer are to the AirVPN server IP's (to reconnect) and the local 192.168.1.0/24 network (to still function in the LAN). And the only connections allowed TO the computer are from the local network as well. No leaks. Now, the gufw GUI doesn't allow for specifying the interface (remember, it's over simplified), so to do that, it's necessary to use ufw directly. Gufw can, however, display the rules when created by ufw. For example: "sudo allow out on tun0 from any to any" - is quite straightforward, and of course creates the rule that allows for communication TO the Internet when connected to AirVPN. "sudo allow in on tun0 from any to any port xxxxx" - enables the port forwarding feature by allowing packets to the specified port on the tun0 interface to pass through. Tips: - the order of the rules is very important - mimic mine on the screenshot attached - to add rules in a specific order from the command line, use "insert x": "sudo insert 3 allow in on tun0 from any to any port xxxxx" - inserts the rule at the 3rd position and moves rules below it downward, includin the previous rule nr 3. - when adding rules via the commandline, press F5 in gufw to force a refresh and view the newly added rule - the UFW manual is well worth reading, although you may not need any more information than offered in this post - with this approach, you're blocking multicasting addresses possibly forwarded by your router. Just a thing to have in mind in case you need it; it is of couse easily remedied by creating a new rule allowing the address(es). Let me know how this works for ya

so i am using ufw as killswitch for my openvpn connection using this tutorial https://gist.github.com/Necklaces/18b68e80bf929ef99312b2d90d0cded2 i can download torrents with no problem, but when it comes to seeding i have to disable ufw to make it work . i have tried different torrent clients, whitelisted the torrent clients with gufw but no success so far .

Is there an IP Range I should be adding to my Firewall? If I run dmesg I have a lot of this: [ 9489.598148] FW6 REJECT (input): IN=enp1s0 OUT= MAC=33:33:00:00:00:01:48:4e:fc:f0:69:b8:86:dd SRC=fe80:0000:0000:0000:4a4e:fcff:fef0:69b8 DST=ff02:0000:0000:0000:0000:0000:0000:0001 LEN=168 TC=0 HOPLIMIT=255 FLOWLBL=356592 PROTO=ICMPv6 TYPE=134 CODE=0 [ 9492.373944] IPv4: martian source 192.168.0.91 from 82.94.183.165, on dev enp1s0 [ 9492.373953] ll header: 00000000: 30 9c 23 47 64 c5 48 4e fc f0 69 b8 08 00 [ 9492.600804] FW6 REJECT (input): IN=enp1s0 OUT= MAC=33:33:00:00:00:01:48:4e:fc:f0:69:b8:86:dd SRC=fe80:0000:0000:0000:4a4e:fcff:fef0:69b8 DST=ff02:0000:0000:0000:0000:0000:0000:0001 LEN=168 TC=0 HOPLIMIT=255 FLOWLBL=356592 PROTO=ICMPv6 TYPE=134 CODE=0 [ 9495.603941] FW6 REJECT (input): IN=enp1s0 OUT= MAC=33:33:00:00:00:01:48:4e:fc:f0:69:b8:86:dd SRC=fe80:0000:0000:0000:4a4e:fcff:fef0:69b8 DST=ff02:0000:0000:0000:0000:0000:0000:0001 LEN=168 TC=0 HOPLIMIT=255 FLOWLBL=356592 PROTO=ICMPv6 TYPE=134 CODE=0 Is there an IP Range or port I should add to my firewall to get this to quit? I've read posts on here mentioning Port 53. And I would like the VPN to be on when I reboot my machine, without having to log in all the time. Is that possible? Thanks

hey guys, with ufw enabled, vpn connects but wget and web pages don't resolve: $uname -a Linux 4.4.0-38-generic #57-Ubuntu SMP Tue Sep 6 2016 x86_64 x86_64 x86_64 GNU/Linux $ufw reset $ufw allow out on wlp1s0 to 213.152.161.180 port 443 proto udp $ufw allow out on tun0 $ufw status verbose Status: active Logging: on (low) Default: deny (incoming), deny (outgoing), disabled (routed) New profiles: skip To Action From -- ------ ---- 213.152.161.180 443/udp ALLOW OUT Anywhere on wlp1s0 # NL-Alblasserdam_Alchiba_UDP-443.ovpn Anywhere ALLOW OUT Anywhere on tun0 # tun0 $openvpn --config ~/VPN/NL-Alblasserdam_Alchiba_UDP-443.ovpn Mon Oct 3 2016 OpenVPN 2.3.10 x86_64-pc-linux-gnu [SSL (OpenSSL)] [LZO] [EPOLL] [PKCS11] [MH] [IPv6] built on Feb 2 2016 Mon Oct 3 2016 library versions: OpenSSL 1.0.2g 1 Mar 2016, LZO 2.08 Mon Oct 3 2016 Control Channel Authentication: tls-auth using INLINE static key file Mon Oct 3 2016 Outgoing Control Channel Authentication: Using 160 bit message hash 'SHA1' for HMAC authentication Mon Oct 3 2016 Incoming Control Channel Authentication: Using 160 bit message hash 'SHA1' for HMAC authentication Mon Oct 3 2016 Socket Buffers: R=[212992->212992] S=[212992->212992] Mon Oct 3 2016 UDPv4 link local: [undef] Mon Oct 3 2016 UDPv4 link remote: [AF_INET]213.152.161.180:443 Mon Oct 3 2016 TLS: Initial packet from [AF_INET]213.152.161.180:443, sid=b2d0c912 4505e529 Mon Oct 3 2016 VERIFY OK: depth=1, C=IT, ST=IT, L=Perugia, O=airvpn.org, CN=airvpn.org CA, emailAddress=info@airvpn.org Mon Oct 3 2016 Validating certificate key usage Mon Oct 3 2016 ++ Certificate has key usage 00a0, expects 00a0 Mon Oct 3 2016 VERIFY KU OK Mon Oct 3 2016 Validating certificate extended key usage Mon Oct 3 2016 ++ Certificate has EKU (str) TLS Web Server Authentication, expects TLS Web Server Authentication Mon Oct 3 2016 VERIFY EKU OK Mon Oct 3 2016 VERIFY OK: depth=0, C=IT, ST=IT, L=Perugia, O=airvpn.org, CN=server, emailAddress=info@airvpn.org Mon Oct 3 2016 Data Channel Encrypt: Cipher 'AES-256-CBC' initialized with 256 bit key Mon Oct 3 2016 Data Channel Encrypt: Using 160 bit message hash 'SHA1' for HMAC authentication Mon Oct 3 2016 Data Channel Decrypt: Cipher 'AES-256-CBC' initialized with 256 bit key Mon Oct 3 2016 Data Channel Decrypt: Using 160 bit message hash 'SHA1' for HMAC authentication Mon Oct 3 2016 Control Channel: TLSv1.2, cipher TLSv1/SSLv3 DHE-RSA-AES256-GCM-SHA384, 4096 bit RSA Mon Oct 3 2016 [server] Peer Connection Initiated with [AF_INET]213.152.161.180:443 Mon Oct 3 2016 SENT CONTROL [server]: 'PUSH_REQUEST' (status=1) Mon Oct 3 2016 PUSH: Received control message: 'PUSH_REPLY,redirect-gateway def1 bypass-dhcp,dhcp-option DNS 10.4.0.1,comp-lzo no,route-gateway 10.4.0.1,topology subnet,ping 10,ping-restart 60,ifconfig 10.4.48.174 255.255.0.0' Mon Oct 3 2016 OPTIONS IMPORT: timers and/or timeouts modified Mon Oct 3 2016 OPTIONS IMPORT: LZO parms modified Mon Oct 3 2016 OPTIONS IMPORT: --ifconfig/up options modified Mon Oct 3 2016 OPTIONS IMPORT: route options modified Mon Oct 3 2016 OPTIONS IMPORT: route-related options modified Mon Oct 3 2016 OPTIONS IMPORT: --ip-win32 and/or --dhcp-option options modified Mon Oct 3 2016 ROUTE_GATEWAY 10.42.0.1/255.255.255.0 IFACE=wlp1s0 HWADDR=xx:xx:xx:xx:xx:xx Mon Oct 3 2016 TUN/TAP device tun0 opened Mon Oct 3 2016 TUN/TAP TX queue length set to 100 Mon Oct 3 2016 do_ifconfig, tt->ipv6=0, tt->did_ifconfig_ipv6_setup=0 Mon Oct 3 2016 /sbin/ip link set dev tun0 up mtu 1500 Mon Oct 3 2016 /sbin/ip addr add dev tun0 10.4.48.174/16 broadcast 10.4.255.255 Mon Oct 3 2016 /sbin/ip route add 213.152.161.180/32 via 10.42.0.1 Mon Oct 3 2016 /sbin/ip route add 0.0.0.0/1 via 10.4.0.1 Mon Oct 3 2016 /sbin/ip route add 128.0.0.0/1 via 10.4.0.1 Mon Oct 3 2016 Initialization Sequence Completed $route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 10.4.0.1 128.0.0.0 UG 0 0 0 tun0 0.0.0.0 10.42.0.1 0.0.0.0 UG 600 0 0 wlp1s0 10.4.0.0 0.0.0.0 255.255.0.0 U 0 0 0 tun0 10.42.0.0 0.0.0.0 255.255.255.0 U 600 0 0 wlp1s0 128.0.0.0 10.4.0.1 128.0.0.0 UG 0 0 0 tun0 169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 wlp1s0 213.152.161.180 10.42.0.1 255.255.255.255 UGH 0 0 0 wlp1s0 $ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: wlp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000 link/ether xx:xx:xx:xx:xx:xx brd ff:ff:ff:ff:ff:ff inet 10.42.0.9/24 brd 10.42.0.255 scope global wlp1s0 valid_lft forever preferred_lft forever inet6 <removed>/64 scope link valid_lft forever preferred_lft forever 3: tun0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN group default qlen 100 link/none inet 10.4.48.174/16 brd 10.4.255.255 scope global tun0 valid_lft forever preferred_lft forever inet6 <removed>/64 scope link flags 800 valid_lft forever preferred_lft forever i don't usually touch my iptables directly but here's the output: $iptables -L Chain INPUT (policy DROP) target prot opt source destination ufw-before-logging-input all -- anywhere anywhere ufw-before-input all -- anywhere anywhere ufw-after-input all -- anywhere anywhere ufw-after-logging-input all -- anywhere anywhere ufw-reject-input all -- anywhere anywhere ufw-track-input all -- anywhere anywhere Chain FORWARD (policy DROP) target prot opt source destination ufw-before-logging-forward all -- anywhere anywhere ufw-before-forward all -- anywhere anywhere ufw-after-forward all -- anywhere anywhere ufw-after-logging-forward all -- anywhere anywhere ufw-reject-forward all -- anywhere anywhere ufw-track-forward all -- anywhere anywhere Chain OUTPUT (policy DROP) target prot opt source destination ufw-before-logging-output all -- anywhere anywhere ufw-before-output all -- anywhere anywhere ufw-after-output all -- anywhere anywhere ufw-after-logging-output all -- anywhere anywhere ufw-reject-output all -- anywhere anywhere ufw-track-output all -- anywhere anywhere Chain ufw-after-forward (1 references) target prot opt source destination Chain ufw-after-input (1 references) target prot opt source destination ufw-skip-to-policy-input udp -- anywhere anywhere udp dpt:netbios-ns ufw-skip-to-policy-input udp -- anywhere anywhere udp dpt:netbios-dgm ufw-skip-to-policy-input tcp -- anywhere anywhere tcp dpt:netbios-ssn ufw-skip-to-policy-input tcp -- anywhere anywhere tcp dpt:microsoft-ds ufw-skip-to-policy-input udp -- anywhere anywhere udp dpt:bootps ufw-skip-to-policy-input udp -- anywhere anywhere udp dpt:bootpc ufw-skip-to-policy-input all -- anywhere anywhere ADDRTYPE match dst-type BROADCAST Chain ufw-after-logging-forward (1 references) target prot opt source destination LOG all -- anywhere anywhere limit: avg 3/min burst 10 LOG level warning prefix "[UFW BLOCK] " Chain ufw-after-logging-input (1 references) target prot opt source destination LOG all -- anywhere anywhere limit: avg 3/min burst 10 LOG level warning prefix "[UFW BLOCK] " Chain ufw-after-logging-output (1 references) target prot opt source destination LOG all -- anywhere anywhere limit: avg 3/min burst 10 LOG level warning prefix "[UFW BLOCK] " Chain ufw-after-output (1 references) target prot opt source destination Chain ufw-before-forward (1 references) target prot opt source destination ACCEPT all -- anywhere anywhere ctstate RELATED,ESTABLISHED ACCEPT icmp -- anywhere anywhere icmp destination-unreachable ACCEPT icmp -- anywhere anywhere icmp source-quench ACCEPT icmp -- anywhere anywhere icmp time-exceeded ACCEPT icmp -- anywhere anywhere icmp parameter-problem ACCEPT icmp -- anywhere anywhere icmp echo-request ufw-user-forward all -- anywhere anywhere Chain ufw-before-input (1 references) target prot opt source destination ACCEPT all -- anywhere anywhere ACCEPT all -- anywhere anywhere ctstate RELATED,ESTABLISHED ufw-logging-deny all -- anywhere anywhere ctstate INVALID DROP all -- anywhere anywhere ctstate INVALID ACCEPT icmp -- anywhere anywhere icmp destination-unreachable ACCEPT icmp -- anywhere anywhere icmp source-quench ACCEPT icmp -- anywhere anywhere icmp time-exceeded ACCEPT icmp -- anywhere anywhere icmp parameter-problem ACCEPT icmp -- anywhere anywhere icmp echo-request ACCEPT udp -- anywhere anywhere udp spt:bootps dpt:bootpc ufw-not-local all -- anywhere anywhere ACCEPT udp -- anywhere 224.0.0.251 udp dpt:mdns ACCEPT udp -- anywhere 239.255.255.250 udp dpt:1900 ufw-user-input all -- anywhere anywhere Chain ufw-before-logging-forward (1 references) target prot opt source destination Chain ufw-before-logging-input (1 references) target prot opt source destination Chain ufw-before-logging-output (1 references) target prot opt source destination Chain ufw-before-output (1 references) target prot opt source destination ACCEPT all -- anywhere anywhere ACCEPT all -- anywhere anywhere ctstate RELATED,ESTABLISHED ufw-user-output all -- anywhere anywhere Chain ufw-logging-allow (0 references) target prot opt source destination LOG all -- anywhere anywhere limit: avg 3/min burst 10 LOG level warning prefix "[UFW ALLOW] " Chain ufw-logging-deny (2 references) target prot opt source destination RETURN all -- anywhere anywhere ctstate INVALID limit: avg 3/min burst 10 LOG all -- anywhere anywhere limit: avg 3/min burst 10 LOG level warning prefix "[UFW BLOCK] " Chain ufw-not-local (1 references) target prot opt source destination RETURN all -- anywhere anywhere ADDRTYPE match dst-type LOCAL RETURN all -- anywhere anywhere ADDRTYPE match dst-type MULTICAST RETURN all -- anywhere anywhere ADDRTYPE match dst-type BROADCAST ufw-logging-deny all -- anywhere anywhere limit: avg 3/min burst 10 DROP all -- anywhere anywhere Chain ufw-reject-forward (1 references) target prot opt source destination Chain ufw-reject-input (1 references) target prot opt source destination Chain ufw-reject-output (1 references) target prot opt source destination Chain ufw-skip-to-policy-forward (0 references) target prot opt source destination DROP all -- anywhere anywhere Chain ufw-skip-to-policy-input (7 references) target prot opt source destination DROP all -- anywhere anywhere Chain ufw-skip-to-policy-output (0 references) target prot opt source destination DROP all -- anywhere anywhere Chain ufw-track-forward (1 references) target prot opt source destination Chain ufw-track-input (1 references) target prot opt source destination Chain ufw-track-output (1 references) target prot opt source destination Chain ufw-user-forward (1 references) target prot opt source destination Chain ufw-user-input (1 references) target prot opt source destination Chain ufw-user-limit (0 references) target prot opt source destination LOG all -- anywhere anywhere limit: avg 3/min burst 5 LOG level warning prefix "[UFW LIMIT BLOCK] " REJECT all -- anywhere anywhere reject-with icmp-port-unreachable Chain ufw-user-limit-accept (0 references) target prot opt source destination ACCEPT all -- anywhere anywhere Chain ufw-user-logging-forward (0 references) target prot opt source destination Chain ufw-user-logging-input (0 references) target prot opt source destination Chain ufw-user-logging-output (0 references) target prot opt source destination Chain ufw-user-output (1 references) target prot opt source destination ACCEPT udp -- anywhere 213.152.161.180 udp dpt:https ACCEPT all -- anywhere anywhere any help would be great. let me know if you need anymore info.

Hi, I've been using ufw/gufw for a long time now to prevent leaks which works great after I followed worric's guide https://airvpn.org/topic/5586-prevent-leaks-with-linux-firestarter-also-stop-traffic-when-vpn-drops/?do=findComment&comment=5642 ​However there's one drawback, which is that all IP's must be resolved prior to connecting because the DNS resolution doesn't get through the firewall. The problem with this is that you can't let it choose the best server for the area/region by resolving for instance gb.vpn.airdns.org. It seems that the best you can do is get a random selection from the list of servers. Is there a way around this? For example to only let that dns query through? or am I wrong somehow? Any clarification is greatly appreciated! ​ Edit: Grammar

How do you configure the firewall (I'm wondering about both Comodo (Windows) and GUFW (Linux)) when using Air VPN over TOR? Or, are the firewall settings to prevent leaks the same as if I were just using Air VPN? Assuming I was fine with my ISP seeing that I'm using TOR, is there any reason to choose TOR over VPN instead of VPN over TOR? I read the TOR page on this site, but I just want to be sure there aren't cases in which I shouldn't choose VPN over TOR. I've heard some people talk about wanting to hide from their ISP the fact that they are using TOR. Why is this? Do some ISPs not tolerate their customers using TOR?