[vpn-help] [DETAILS ON ISSUE] Shrew and Changing MAC Address (can it be done)

Larry larry at halfordhide.com
Tue Mar 19 10:47:42 CDT 2013


Hello:

I have looked online at other VPN Clients. Our hardware vendor supports
their own and Shrew so I am hoping to get Shrew to work for my unique
situation.

Here is the issue:
Our Phone PBX Is behind our corporate firewall. We have some off-site
users that use VPN (switching to shrew). To IPSEC in to LAN/DHCP.

The off-site computer is equipped with a Software Phone made for our
PBX. Since the Softphone has no MAC of its own it BINDS to an adapter to
get a MAC Address for its use (BINDS to VPN Adapter).
Once Shrew connects to Corporate and the phone is launched it connects
to the PBX.

Inside the PBX it does 3 things.
1.  Looks at the MAC ADDRESS that the phone is registered to.
2. REMEMBERS the IP to where to send data
3. ASSIGNS the software phone a phone extension BASED ON the MAC of the
device.

Problems happen when we have TWO Computers setup

Computer 1 CONNECTS TO PBX. Given ext '555' based on (shrew VPN MAC).
Computer 2 CONNECTS TO PBX. Given ext '555' based on (Shrew  VPN MAC).

Computer 1 LOOSES connection when PBX gave it to Computer 2 and when it
pings back, PBX reconnects computer 1 to ext '555'
Computer 2 LOOSES connection and asks for its ext. PBX gives it '555'
based on MAC
BOTH phones then are useless as the PBX is giving the SAME phone ext
based on MAC Address.

I understand that MAC is not needed in an IPSEC/DHCP mode but the
off-site system NEEDS a different MAC Address.

SOLUTION:
A great solution would be to provision SHREW to allow a set STATIC MAC
Address for computer1 that will stay the SAME every time it connects AND
allow me to set independent MAC Addresses to other systems that do the
same.

THEN every time the softphone that binds to the VPN MAC will get its
proper phone extension from the PBX and all offsite phones will work
correctly.

Please advise how I can accomplish this task.

Respectfully,



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