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OneMintJulep

Member

Registered: 2013-10-23

Posts: 7

VPN Bytes sent But Zero Received

I'm having trouble setting up a VPN connection to my work and am sort of a noob when it comes to networking. After connecting through our VPN portal I can see bytes being sent but zero bytes are received and I can't load any webpage. I can see that the VPN client is running and a tuntap device is created.

3: tun0: <POINTOPOINT,MULTICAST,NOARP> mtu 1500 qdisc noop state DOWN group default qlen 500
    link/none

I tried doing ip link set tun0 up which resulted in:

3: tun0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN group default qlen 500
    link/none

I'm guessing the state UNKNOWN and link/none are signs that something's not right but I don't know where to go from there. Any wisdom would be much appreciated.

Gcool

Member

Registered: 2011-08-16

Posts: 1,456

Re: VPN Bytes sent But Zero Received

There's not really much info to go on here.

- What type of vpn setup are you using (openvpn, cisco,...)?
- What are you trying to accomplish (all traffic being routed through the tunnel or only specific subnets)?
- How's it configured (aka config files)?
- What's the output of "ip addr" and "ip route" after the tunnel is established?
- Journal/log entries of when you up/down the vpn?

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Burninate!

OneMintJulep

Member

Registered: 2013-10-23

Posts: 7

Re: VPN Bytes sent But Zero Received

The client I'm using is Array SSL VPN and ultimately I'd like to be able to ssh to remote machines and access internal web pages so I guess I want all traffic routed. The client assigns me an ip address and I've tried adding it to the tun0 device but it's state remains UNKNOWN. I cannot find any config files related to this VPN client. The output of ip addr is :

4: tun0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN group default qlen 500
    link/none 
    inet ##.##.###.##/## scope global tun0
       valid_lft forever preferred_lft forever

the output of ip route is:

default via 192.168.0.1 dev enp8s0  metric 202 
192.168.0.0/24 dev enp8s0  proto kernel  scope link  src 192.168.0.104  metric 202

What should I be routing to/from the tun0 device?

Gcool

Member

Registered: 2011-08-16

Posts: 1,456

Re: VPN Bytes sent But Zero Received

I'm not familiar with Array SSL VPN, I must admit (did a quick Google search, but information seems to be limited).

Is it a "normal" clientless vpn (aka, you browse to a certain webpage, login and that should theoretically be it) or did you have to install something?

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OneMintJulep

Member

Registered: 2013-10-23

Posts: 7

Re: VPN Bytes sent But Zero Received

Yeah it doesn't seem too popular. In practice I should be able to just login to a webpage and be done, but there is a client installed on my computer that gets launched through java every time I connect so I guess it's not "clientless". When I login I get a window which displays the number of bytes sent and received. The bytes sent number grows but the bytes received number remains zero which makes me think that it's a routing problem.

P.S. Thanks for looking into it.

Gcool

Member

Registered: 2011-08-16

Posts: 1,456

Re: VPN Bytes sent But Zero Received

I figured that much. Most similar solutions (Juniper,...) use java applets.

The problem is indeed that your routing is not getting set up correctly. When you look at your "ip route" setup, you'll see that nothing actually gets routed over the vpn (tun0 interface). Unfortunately, it's the java applet that's responsible for doing all this (without any sort of configuration on your part).

If your company (I assume that's what you're using it for?) has any sort of support contacts with Array, it might be useful to check if their solution supports linux and if they have any guidelines on what the requirements are.

Sorry I can't be of more help.

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Burninate!

OneMintJulep

Member

Registered: 2013-10-23

Posts: 7

Re: VPN Bytes sent But Zero Received

I've tried our support group and they weren't too knowledgable but I'll keep poking and proding. Thanks for the help.