RE: VPN with Exchange issue
"Hart, Kevin" <[email protected]> Wed, 8 Dec 2004 17:15:33 -0500
| Newsgroups | gmane.comp.security.vpn |
|---|---|
| Message-ID | <[email protected]> |
Paul, The route statement can be executed from a command prompt on any Windows machine. This would be done after you have connected with VPN. Kevin -----Original Message----- From: Dube, Paul [mailto:[email protected]] Sent: Wednesday, December 08, 2004 7:36 AM To: Hart, Kevin Cc: [email protected] Subject: Re: [VPN] VPN with Exchange issue Thanks Kevin & all who replied, I am new to the list and was not aware of the 'reply directly to responder' rule. Since this contains new information, I am sure it will hit the list and I wanted everyone to know I was grateful. I recently discovered that the client is using the Netscreen VPN client and I do not see anywhere I can specify a route or the execution of a batch file. If I replace the Netscreen startup with a batch file, will that do the same thing? Thanks in advance, Paul Hart, Kevin wrote: > Paul, > > If the destination IP address is in the same subnet as the hotel assigned IP > address, the client is going to ARP on the local network to find the > Exchange server unless you assign a discrete route to the remote Exchange > server with a 32 bit mask. > This problem does occur with the Shiva product, but it also occurs with the > Cisco VPN as well. I've been able to get around it by adding a route to the > client's machine with a destination IP address of the Exchange server on the > remote LAN and a gateway pointing to the DHCP assigned address on the VPN > client. > > For Example: > > Local IP address assigned at hotel: 192.168.1.32 > VPN assigned IP address: 192.168.50.30 > Remote address of Exchange Server: 192.168.1.5 > > Route Statement: Route add 192.168.1.5 mask 255.255.255.255 192.168.50.30 > > You will probably need to add routes for your remote DNS and WINS server in > the same fashion. > > This is definitely a cumbersome process, but it does work. If anyone has > better ideas or solutions, I'd like to hear them. > > Thanks, > Kevin > > > > > -----Original Message----- > From: Dube, Paul [mailto:[email protected]] > Sent: Tuesday, November 30, 2004 8:14 PM > To: [email protected] > Subject: [VPN] VPN with Exchange issue > > Greetings all, > I have a client that is presenting me with a new issue for which I do > not yet have all the facts. I will be on site tomorrow and hope to at > least get those. However, from what I have gathered so far, they are > using Outlook and Exchange with a custom developed application using > public folders. The data in the public folders must be available when > not connected so it must use the 'available offline' aspect of that > combination. > I am not completely familiar with Outlook/Exchange but I believe that > this synchronization of content only transpires when using the native > connect mode which is not commonly available without a VPN. My client is > using the Shiva VPN client to connect to the LAN and access the Exchange > server. The issue arises when they are in a hotel or other location with > a LAN in the same subnet (192.169.1.255) and there is a machine on the > LAN at the same IP address as the exchange server on the corporate LAN. > I am wondering if simply putting the Exchange server on an IP unlikely > to be assigned to a machine on another LAN, using a reserved address and > 1-1 NAT, or routing the connection over an SSH redirect would be a > workable solution. I am also wondering if the issue only arises due to > an oversight in initial implementation and the Shiva VPN can be > configured to route all requests on the specified ports over the VPN to > a remote machine, ignoring any local machine with the same IP address. > > Thank in advance, > Paul Dube > > Paul Dube <[email protected]> > _______________________________________________ > VPN mailing list > [email protected] > http://lists.shmoo.com/mailman/listinfo/vpn >