Linksys 8 port router and VPN/SAP connection problem

Archived from groups: comp.dcom.vpn (More info?)

Hi, we are using Linksys EtherFastCable/DSL Router with 8-Port Switch
(BEFSR81) and we are having problem using Nortel VPN program and
SAPlogon. We lose the connection all the time, when we use both VPN
and SAPlogon.
This is what I have done so far.
1. Enable "Multicast Pass Through", "IPSec Pass Through ","PPTP Pass
Through" and "PPOE Pass Through".
2. Disable "Block anonymous internet request".
3. added following ports under "port triggering".: 500, 3100-3900, 4,
137, 2745, 4138, 1080
4. Enable "MTU" the size is 1492.

Is there anything else I could do resolve the problem? Does anyone
know which ports Nortel VPN and SAP logon use, except above? There is
no firmware to upgrade. Thanks in advance!