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Using a router in front of ISA for PPPoE - 12.Jul.2005 3:22:00 PM

kegan

Posts: 15
Joined: 12.Jul.2005
Status: offline

I have heard that this is the best way to avoid issues relating to DHCP/MTU and other stability and reliability issues with PPPoE DSL connections.

My plan is to put a SOHO router in front of ISA 2004 (running on SBS 2003). Here's the configuration as I envision it:

Internal IP for SBS NIC: 192.168.16.2/24
External IP for SBS WAN NIC: 10.0.0.2/24
SOHO Router LAN IP: 10.0.0.10/24
SOHO Router WAN (PPPoE static) IP: 64.26.175.52

I assume the ISA server will be performing NAT to the 10.0.0.x network. The SOHO router by default will perform NAT again to the Internet. Correct? Are there issues with this and is this the correct configuration?

2. Am I correct that to host services on my internal network, I will need to configure rules on ISA and port forwarding to 10.0.0.2 on the SOHO router?

3. We will use OWA, RWW, RPC over HTTP, and VPN. Will this configuration even work for services like VPN? If not, what changes need ot be made?

Your clarification and guidance is appreciated.

Kevin

Post #: 1

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RE: Using a router in front of ISA for PPPoE - 12.Jul.2005 10:54:00 PM

tshinder

Posts: 47663
Joined: 10.Jan.2001
From: Texas
Status: offline

Hi Kevin,

1. I assume the ISA server will be performing NAT to the 10.0.0.x network. The SOHO router by default will perform NAT again to the Internet. Correct? Are there issues with this and is this the correct configuration?
TOM: There are no issues. If you find speed is a bit slower than you expected, try enabling PMTU discovery on the ISA firewall.

2. Am I correct that to host services on my internal network, I will need to configure rules on ISA and port forwarding to 10.0.0.2 on the SOHO router?
TOM: Yes, works great, including VPN PPTP and L2TP/IPSec!

3. We will use OWA, RWW, RPC over HTTP, and VPN. Will this configuration even work for services like VPN? If not, what changes need ot be made?
TOM: I don't know anything about RWW, but all the other services work fine.
HTH,
Tom

(in reply to kegan)