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Elleni
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Joined: 23 May 2006
Posts: 1291
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 Posted: Sat Apr 09, 2016 6:24 pm Post subject: [solved] Openvpn Server - Routing internet traffic |
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I installed openvpn server and am able to connect from an android system to openvpn. I also can see a webpage, hosted on the openvpn server which has also installed apache on it.
But I cannot reach other internet sites.
What is needed to route all traffic comming from openvpn client to internet? Can this be acheaved with adding a route into routing table of the server, or do I have to use iptables? I have no firewall installed on the server for the moment.
| Code: | port 1234
proto udp
dev tun
ca /etc/openvpn/certs/ca.crt
cert /etc/openvpn/certs/server.crt
key /etc/openvpn/certs/server.key
dh /etc/openvpn/certs/dh4096.pem
tls-auth /etc/openvpn/certs/ta.key 0
server 10.8.1.0 255.255.255.0
push "redirect-gateway def1 bypass-dhcp"
persist-key
persist-tun
topology subnet
keepalive 10 120
local myipadress of the server
user openvpn
group openvpn
# client-to-client
comp-lzo
log /var/log/openvpn.log
status /var/log/openvpn-status.log
verb 5
mute 20
client-config-dir ccd
route 10.8.1.0 255.255.255.0 |
When I try to access a website on internet, I see
| Code: | | bad source address from client [10.216.50.110], packet dropped |
on the openvpn server's log
Last edited by Elleni on Sat Apr 16, 2016 2:21 pm; edited 2 times in total |
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gerdesj
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Joined: 29 Sep 2005
Posts: 622
Location: Yeovil, Somerset, UK
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| Posted: Sat Apr 09, 2016 10:30 pm Post subject: Re: Openvpn Server - Routing internet traffic |
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For OpenVPN clients to access the internet:
Routing (forwarding) must be enabled on the server (echo 1 > /proc/sys/net/ipv4/ip_forward, /etc/sysctl.d/, or similar that will set that entry)
The clients must have a default gateway route that goes via the OVPN server
The server must have a NAT rule for the OVPN clients
The firewall must permit the traffic
You are probably missing out one of those items. You can run Wireshark (or tcpdump to file and read it via Wireshark elsewhere) and watch the traffic. Remember you can't see network traffic and guessing rarely works out!
Cheers
Jon |
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Elleni
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Joined: 23 May 2006
Posts: 1291
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| Posted: Sun Apr 10, 2016 10:37 am Post subject: |
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| First 2 points are OK. But I dont habe iptables installed in the server. Can a nat roule be implemented without iptables vor do I habe to install iptables on server for creating a nat rule? |
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gerdesj
l33t
Joined: 29 Sep 2005
Posts: 622
Location: Yeovil, Somerset, UK
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| Posted: Sun Apr 10, 2016 11:18 am Post subject: |
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| Elleni wrote: | | First 2 points are OK. But I dont habe iptables installed in the server. Can a nat roule be implemented without iptables vor do I habe to install iptables on server for creating a nat rule? |
NAT is a firewall function and hence iptables is needed if you want to do it at the the OpenVPN server. However - unless your OVPN server has an external address - you actually have to do the NAT at your router. You will also need a static route on your router for the OVPN network which points back at your OVPN server.
Client <-> Server (OVPN network) <-> OVPN server (LAN) <-> Router (LAN) <-> Router (WAN) <-> ISP <-> Internet <-> Target
All the <-> above are routes and all devices need to "know" about the routes between all the others. You probably have all of them defined apart from Server (OVPN network) <-> Router (LAN) on Router. The NAT at Router (WAN) hides all your stuff behind itself which avoids you having to run BGP and of course your ISP takes care of your routes in the outside world. |
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Elleni
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Joined: 23 May 2006
Posts: 1291
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| Posted: Mon Apr 11, 2016 6:58 am Post subject: |
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Understood. Thanks for detailed answer. As the Server is a virtual Server and I have no router inbetween that I could configure, and I access Server by it's public adress, I understand now, that I will have to implement iptables for nat, and I will also add needed route(s) in order to let my openvpn Server secure my internet access via mobile device.
I will put [solved}]as soon as I am done, but this could take a while 
In the meantime I once more thank you for the awesome Support in this foum!  |
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gerdesj
l33t
Joined: 29 Sep 2005
Posts: 622
Location: Yeovil, Somerset, UK
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| Posted: Mon Apr 11, 2016 8:00 am Post subject: |
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As the OVPN server has a public IP address then you will not need much in the way of routing because it "knows" where all its interfaces are already.
Please get a firewall installed as soon as possible. There are several great packages eg Shorewall and ufw which will make managing rules easier or you can simply write a script. If you are using OpenRC you can put the rules in /etc/conf.d/net in postup() { } and postdown() { }
Good luck! |
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Elleni
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Joined: 23 May 2006
Posts: 1291
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| Posted: Wed Apr 13, 2016 8:50 pm Post subject: |
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ok, I have iptables up and running with the help of:
https://wiki.gentoo.org/wiki/Iptables
and then added:
| Code: |
iptables -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
iptables -A FORWARD -s 10.8.1.0/24 -j ACCEPT
iptables -A FORWARD -j REJECT
iptables -t nat -A POSTROUTING -s 10.8.1.0/24 -o enp0s5 -j MASQUERADE |
Internet access on the vpn client now works; with a little exeption:
When I change
| Code: | | iptables -P INPUT DROP |
I have the problem, that the websites, hosted on the same server are not accessible. But internet access is still working.
As soon as I change the input table to accept, I have access to my website too.
Following the iptables rules that I have set, perhaps someone sees what I should change in order to be able to access internet including my own website hosted on the same server from the vpn client - with input table set to drop.
| Code: | iptables -L
Chain INPUT (policy ACCEPT)
target prot opt source destination
ACCEPT all -- anywhere anywhere ctstate RELATED,ESTABLISHED
ACCEPT all -- anywhere anywhere
ACCEPT icmp -- anywhere anywhere icmp destination-unreachable
ACCEPT icmp -- anywhere anywhere icmp time-exceeded
ACCEPT icmp -- anywhere anywhere icmp parameter-problem
REJECT tcp -- anywhere anywhere tcp dpt:auth flags:FIN,SYN,RST,ACK/SYN reject-with tcp-reset
ACCEPT tcp -- anywhere anywhere tcp dpt:ssh flags:FIN,SYN,RST,ACK/SYN ctstate NEW
ACCEPT tcp -- anywhere anywhere tcp dpt:smtp flags:FIN,SYN,RST,ACK/SYN ctstate NEW
ACCEPT tcp -- anywhere anywhere tcp dpt:https flags:FIN,SYN,RST,ACK/SYN ctstate NEW
ACCEPT tcp -- anywhere anywhere tcp dpt:imaps flags:FIN,SYN,RST,ACK/SYN ctstate NEW
ACCEPT tcp -- anywhere anywhere tcp dpt:submission flags:FIN,SYN,RST,ACK/SYN ctstate NEW
ACCEPT tcp -- anywhere anywhere tcp dpt:imap flags:FIN,SYN,RST,ACK/SYN ctstate NEW
ACCEPT tcp -- anywhere anywhere tcp dpt:http flags:FIN,SYN,RST,ACK/SYN ctstate NEW
ACCEPT tcp -- anywhere anywhere tcp dpt:urd flags:FIN,SYN,RST,ACK/SYN ctstate NEW
ACCEPT tcp -- localhost anywhere tcp dpt:10024 flags:FIN,SYN,RST,ACK/SYN ctstate NEW
ACCEPT tcp -- localhost anywhere tcp dpt:10025 flags:FIN,SYN,RST,ACK/SYN ctstate NEW
ACCEPT tcp -- localhost anywhere tcp dpt:mysql flags:FIN,SYN,RST,ACK/SYN ctstate NEW
ACCEPT tcp -- anywhere anywhere tcp dpt:openvpn-port flags:FIN,SYN,RST,ACK/SYN ctstate NEW
Chain FORWARD (policy DROP)
target prot opt source destination
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
ACCEPT all -- 10.8.1.0/24 anywhere
REJECT all -- anywhere anywhere reject-with icmp-port-unreachable
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
iptables -L -t nat
Chain PREROUTING (policy ACCEPT)
target prot opt source destination
Chain INPUT (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
Chain POSTROUTING (policy ACCEPT)
target prot opt source destination
MASQUERADE all -- 10.8.1.0/24 anywhere
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gerdesj
l33t
Joined: 29 Sep 2005
Posts: 622
Location: Yeovil, Somerset, UK
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| Posted: Wed Apr 13, 2016 11:56 pm Post subject: |
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You are nearly there. Could you post the output from the following:
#ip a
#ip r
#netstat -leepn | grep 80
I assume your webserver is listening on :80 (substitute apache or nginx if more appropriate.)
Cheers
Jon |
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Elleni
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Joined: 23 May 2006
Posts: 1291
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| Posted: Thu Apr 14, 2016 6:34 am Post subject: |
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| Code: | ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 brd 127.255.255.255 scope host lo
valid_lft forever preferred_lft forever
2: enp0s5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:1c:42:66:08:79 brd ff:ff:ff:ff:ff:ff
inet <ser.ver.ip.address>/24 brd <ser.ver.netw.255 scope global enp0s5
valid_lft forever preferred_lft forever
3: tun0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 100
link/none
inet 10.8.1.1/24 brd 10.8.1.255 scope global tun0
valid_lft forever preferred_lft forever
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| Code: | ip b
Object "b" is unknown, try "ip help".
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| Code: | netstat -leepn | grep 80
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 0 5539 3968/apache2
unix 2 [ ACC ] STREAM HÖRT 5801 4172/master private/rewrite
unix 2 [ ACC ] STREAM HÖRT 5804 4172/master private/bounce
unix 2 [ ACC ] STREAM HÖRT 5807 4172/master private/defer |
Yes and on port 443 too.
| Code: | netstat -leepn | grep apache
tcp 0 0 0.0.0.0:443 0.0.0.0:* LISTEN 0 5536 3968/apache2
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 0 5539 3968/apache2
unix 2 [ ACC ] STREAM HÖRT 54703 29865/apache2 /var/run/cgisock.3968 |
Thanks in advance |
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Elleni
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Joined: 23 May 2006
Posts: 1291
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| Posted: Sat Apr 16, 2016 2:23 pm Post subject: |
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After reflecting a littlebit and after finding out that sending mails did not work eather from my mobile with vpn connection established, I found my error. I had most rules with -i enp0s5 which naturally explains why I could not see webpages, that were requested via tun0. Corrected it and tataaa everything works fine now
Thanks once again for incredible support in this forum! I love my gentoo |
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