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Thread: Server Issue

  1. #1
    Join Date
    Jun 2013
    Beans
    4

    Server Issue

    We are running a mixed environment of windows & ubuntu (12.04 server) primarily for a postgresql based application.

    On the LAN everything works fine. The problems come with trying to access remotely over an IPSEC VPN.

    We can access all of the windows based servers with no problem at all - the ubuntu based machines are completely invisible and it is impossible to connect to them. Ping comes back as destination unreachable (both to and from the ubuntu machines) but works fine to and from all windows machines. (All machines are correctly registered in DNS & WINS)

    Have done sudo ufw disable to try and ensure no firewall issue, both the windows servers and the ubuntu servers receive address via DHCP so network config should be consistent. I assume that as the windows communication works that it is not a VPN issue but am unable to work out what is making the ubuntu box invisible (even nmap is unable to get a response) I am sure it must be somthing obvious - just not sure what!

    Not sure if relevant but all the windows & ubuntu servers are running under ESXi 5.0

    Any help appreciated.

    Andrew
    Last edited by andrew0401; June 25th, 2013 at 03:58 PM.

  2. #2
    Join Date
    Jun 2006
    Location
    Nux Jam
    Beans
    Hidden!
    Distro
    Ubuntu Development Release

  3. #3
    Join Date
    Jun 2013
    Beans
    4

    Re: Confused

    Not really same as can access all functions/ports on local LAN - just no response on any port over the VPN link

  4. #4
    Join Date
    Feb 2008
    Location
    Texas
    Beans
    29,809
    Distro
    Ubuntu 20.04 Focal Fossa

    Re: Server Issue

    Thread moved to Server Platforms. Change title to be descriptive of the issue.

  5. #5
    Join Date
    Nov 2006
    Location
    Belgium
    Beans
    3,025
    Distro
    Ubuntu 10.04 Lucid Lynx

    Re: Server Issue

    Ping comes back as destination unreachable (both to and from the ubuntu machines) but works fine to and from all windows machines. (All machines are correctly registered in DNS & WINS)
    is that ping by hostname ot ping by address ?

    try address if you haven't already

    tun traceroute and compare to see where it stops.

  6. #6
    Join Date
    Nov 2008
    Location
    Boston MetroWest
    Beans
    16,326

    Re: Server Issue

    It sounds to me like the Ubuntu boxes are missing a route to send reply traffic back to you over the VPN tunnel. I don't use IPsec (I much prefer the simplicity of OpenVPN), so I cannot say whether that matters. However if, as an example, your machine has a tunnel address of 10.10.10.10/255.255.255.0, then the Ubuntu machine needs to know that traffic for 10.10.10.0/24 has to be sent to the proxy server rather than to the default gateway.

    Take a look at the routing table on one of the Ubuntu servers with "route -n". Do you see a route for the VPN subnet with the proxy server as its gateway?
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  7. #7
    Join Date
    Dec 2008
    Location
    UK
    Beans
    407
    Distro
    Ubuntu 16.04 Xenial Xerus

    Re: Server Issue

    What is the vpn running on? I have just had fun and shenanigans setting up a connection to my work VPN which uses a Sonicwall device, I got the connection working but couldn't actually access anything, turned out to be a routing problem..

  8. #8
    Join Date
    Jun 2013
    Beans
    4

    Re: Server Issue

    Various answers to the question.

    PING - have tried via ip and via address - no response
    TRACEROUTE - appears to follow correct route, all intermediate machines answer OK but the target machine respons ok to the first packet and then no more

    ROUTE - had assumed that as the windows machine did not need a specific return route then the UBUNTU machines would not so a route -n only shows all routes back to the network gateway/firewall/proxy
    - update - have put a return route onto the ubuntu box - same result with travceroute, first packet from target machine works but then all fail.

    IPSEC is being supported by the network gateway/firewall which is pfsense 2.0. - actually proved very easy to set up

    Andrew
    Last edited by andrew0401; June 27th, 2013 at 08:46 AM.

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