My Network
internet
|
+----------------------+
| |
eth2 |
| |
Firewall-eth1-----netB----ISA
|
eth0
|
netA
Firewall Rules
iptables -t nat -A POSTROUTING -o eth2 -j SNAT --to-source 'external ip
address'
iptables -A FORWARD -i eth0 -o eth2 -m state --state
NEW,RELATED,ESTABLISHED -j ACCEPT
iptables -A FORWARD -i eth2 -o eth0 -m state --state RELATED,ESTABLISHED
-j ACCEPT
iptables -A FORWARD -i eth0 -o eth1 -j ACCEPT
iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT
MS/ISA Server listening for ipsec/l2tp on both adapters
My Problem
If I connect a MS/XP client to the MS/ISA server via ipsec/l2tp directly
from netB or the internet every thing works fine.
If I try to connect from netA through to netB the client fails to connect.
If try to connect from netA to the MS/ISA server via the internet
address all works ok.
The only difference in my rules is that the traffic gets NAT'ed on the
way out to the internet.
I have tried NATing the traffic leaving the firewall on eth1 but this
did not resolve the issue.
I have added -m state rules from eth0 to eth1 and back, this did not help.
The only difference I have seen in the traffic between the connections
through the firewall is a ip-fragment between netA and netB during the
isakmp stage of the connection both then procced to start ESP traffic.
Has anyone seen this type of problem before?
Eventually I do want to remove the ISA server of the internet and route
the ipsec/l2tp traffic through the firewall but I can't do that until i
can get this bit working.
Thanks in advance
Martin
