[pptp-server] linux to linux pptp connection

Jordan Share iso9 at phantasticant.com
Wed Nov 14 13:49:26 CST 2001


Why not NAT the laptops to multiple addresses?  Thus:
10.1.1.1 -> 192.168.1.129
10.1.1.2 -> 192.168.1.130
etc.

Or, just run the PPTP server on the linux box that is directly attached to the lucent basestation.

Jordan
  -----Original Message-----
  From: pptp-server-admin at lists.schulte.org [mailto:pptp-server-admin at lists.schulte.org]On Behalf Of HVR
  Sent: Wednesday, November 14, 2001 9:34 AM
  To: Jordan Share
  Cc: Jerry Vonau; Tom Eastep; knollst at tronicplanet.de; pptp-server at lists.schulte.org
  Subject: Re: [pptp-server] linux to linux pptp connection


  i think we are on to something, but let me explain my setup:

  we have several win/2k and win98 laptops, they all have a orinico wireless card, via this wireless card they connect to the lucent basestation, this lucent basestation is plugged into eth0 of a linux box firewall. the linux box does dhcp so all the laptops get a 10.1.1.0/24 ip address it then does MASQ/NAT and send each packet coming in on eth0, out on eth1 which is connected to our LAN. 

  However it will ONLY forward packets going out on eth1 which are going to the linux box running pptpd. pptpd box then authenticates and assigns ip to the tunnels in the 192.168.1.0/24 range and then NAT/MASQ the packets coming from within the tunnel out into the LAN. doing this forces all over the air traffic (between laptop client and the basestation) to be pptp encrypted (since only packets going to the pptp server are forwarded, and these are encrypted).

  now the problem i have is that when multiple laptop clients are NATed via the linux box firewall then pptp will only set up one tunnel for all of them: quite messy!

  picture(?):

  laptop-W2k/w98
  |
  lucent basestation
  |
  eth0 on linux firewall
      DHCP to laptop
      NAT to eth1
     firewall rule: only packets going to pptp box are let thru
  eth1
  | (this is our LAN)
  |
  pptp box
      authenticate
      NAT but only if from a pptp tunnel
  |
  internal LAN

  With frees/wan i would like to be able to setup IPsec from each laptop, NAT them all via the firewall and have the pptp server (now just running ipsec) be the receiving side.

  so i need some fancy setup and i need ipsec support for win/2k and win/98

  Any comments greatly appreciated.

  Jordan Share wrote:

    Ok, yes. If you have a Linux-to-Linux connection, then I think you'd be better off getting IPSec working, and a tunnel set up between your two subnets.

    Do you have a static IP on both ends?  That is really helpful, but I don't think it's needed (although I can't say for sure, since I do have a static IP on both ends).

    You have to make sure that the subnets that you are using are distinct.  For example, at work we are using the 10.1.1.0/24 subnet, which I have connected to my network at home (192.168.0.0/24).  That way, a route can be set up (FreeS/WAN does this automatically at each end) for the destination subnet, after the IPSec tunnel comes up.

    You end up with something like this:

    LAN1 - 10.1.1.0/24
    |
    10.1.1.1 -- eth0 on linuxbox1
    |
    linuxbox1
    |
    a.b.c.d -- eth1 on linuxbox1
    |
    Internet
    |
    w.x.y.z -- eth1 on linuxbox2
    |
    linuxbox2
    |
    192.168.0.1
    |
    LAN2 - 192.168.0.0/24

    Then machines on my LAN at home send their packets to linuxbox2, which encrypts and tunnels them to linuxbox1, which decrypts and sends them on to the machines on LAN1.

    This kind of thing is really easy to set up with FreeS/WAN.  If you need to do windows browsing and whatnot, then you'd need to fool around with a WINS server for your network neighborhood to connect properly (Samba is working fine for us in this respect, although you probably are already using a WINS server if you have a windows domain).

    Jordan

    ----Original Message-----
    From: pptp-server-admin at lists.schulte.org [mailto:pptp-server-admin at lists.schulte.org] On Behalf Of HVR
    Sent: Tuesday, November 13, 2001 11:55 AM
    To: Jordan Share
    Cc: Jerry Vonau; Tom Eastep; knollst at tronicplanet.de; pptp-server at lists.schulte.org
    Subject: Re: [pptp-server] linux to linux pptp connection




      Jordan Share wrote:

For remote access, it's probably easier to get PPTP "dialin" working.  Freeswan does not support "remote" IPs in the same way.  You do not lease an IP address on the local network, you just encrypt the traffic to and from a given IP/Netmask.  This makes "roadwarrior" dialins a bit tricky.  If you have a static IP on the Win2k box, then it's very easy to set up the IPSec tunneling.  (Well, not easy, perhaps, but doable).  If you want to connect roaming dialin users, then you need to jump through some hoops, or just use PGPNet, or some other IPSec client software to manage things.The original post I was replying to was talking about using PPTP to connect two LANs together.  Which is something that I think is much better done with IPSec.Jordan

      By problem is currently that i have multiple clients behind a linux box doing NAT/masquerading. so when the clients get to the pptp server they all seem to have the same ip address and hence pptp will only create one tunnel per ip and  ALL clients will go thru this, which creates a big mess! i was hoping that we can either change pptp to allow mutliple tunnels per ip-pair or that i can use FreeS/wan somehow.

      The clients are a mix of win/2k/98 they connect to the linux box which will serve them an ip address via dhcp, and then the box will NAT all their packets which are then forwarded to the pptp server. and that is where i get into problems...

      i can explain why i am doing all this in case you are interested.

-----Original Message-----From: pptp-server-admin at lists.schulte.org[mailto:pptp-server-admin at lists.schulte.org]On Behalf Ofhvrietsc at yahoo.comSent: Monday, November 12, 2001 8:30 PMTo: Jordan ShareCc: Jerry Vonau; Tom Eastep; knollst at tronicplanet.de;pptp-server at lists.schulte.orgSubject: Re: [pptp-server] linux to linux pptp connectionok you got me curious, can i do the following with frees/wan:one secure box running frees/wan with one eth to the outside and one ethto the inside.then ca
n i use win-2k and win 98 to connect to freesw/wan? if so whatdo they use for making the tunnels. for pptp connections i just have them use the build in vpn connector or whatever M$ calls this. so what about ipsec? is this supportedby win/2k and win98?On Mon, Nov 12, 2001 at 10:42:35AM -0800, Jordan Share wrote:
I'd have to agree that FreeS/WAN is probably what you want to go with.  I've not had a tunnel go down yet.  (Well, as long as our DSL stays up.)  Also, you have the bonus that it interoperates with other IPSec implementations (an advantage you don't have with vtund).  I set up FreeS/WAN for connectivity to our backside LAN at the colo center (connecting to a Netscreen100 firewall), and since then have been easily able to add in tunnels for my network at home (FreeS/WAN) and to a coworker's Win2k box.Plus, I really feel that the experience you gain in setting up a FreeS/WAN tunnel is far more broadly applicable to other IPSec installations than setting up some proprietary tunneling product (such as vtund).There's no way I'd ever use PPTP to tunnel two LANs together, if I had a choice.  PPTP is for remote access, IMHO.Jordan-----Original Message-----From: pptp-server-admin at lists.schulte.org[mailto:pptp-server-admin at lists.schulte.org]On Behalf Of Jerry VonauSent: Saturday, November 10, 2001 9:50 AMTo: Tom EastepCc: knollst at tronicplanet.de; pptp-server at lists.schulte.orgSubject: Re: [pptp-server] linux to linux pptp connectionTom:Just figured out vtund, I'm testing it now.Have you played with it? Seems stable.Jerry VonauTom Eastep wrote:
On Saturday 10 November 2001 08:28 am, Jerry Vonau wrote:
The fix is to have a reliable isp and hope their upstream is reliable.
Or switch to an IPSEC tunnel -- For Linux<->Linux tunneling, I've foundFreeS/Wan to be more reliable than PPTP.-Tom--Tom Eastep    \  teastep at shorewall.netAIM: tmeastep  \  http://www.shorewall.netICQ: #60745924  \_________________________
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