ICS blocking incoming connections

[Alder]

Hi all,

Up to now I've been running ICS without much problem, both to allow my
LAN clients to share the Interent connection, and to allow Internet
connections to services running on one of my ICS clients. ICS is
running on a W2K Pro SP4 machine; the two ICS clients are on another
W2K Pro machine and an OpenVMS AlphaServer.

After having to reinstall W2K on the ICS host recently, all outgoing
connections to the Internet, and all connections between nodes on my
(peer-to-peer) LAN function normally. Incoming connections from the
Internet, however, are all blocked. An external port scanner,
GRC.COM, reports these ports CLOSED, rather than OPEN.

I can't see why they would be closed, though. All are defined and
enabled under the ICS "Services" tab and have the correct destination
IP on my LAN. ICS itself, of course, is enabled on the ICS host, and
only on the ICS host. I do not run a DNS or DHCP Server anywhere on
the LAN.

Does anyone have any troubleshooting suggestions I could try?

Thanks,

Terry

 

[serverguy]

Did you enable ICS on the correct NIC? It should be on the one you have
connected directly to the internet. Also, you need a better understanding
of ICS. You say you have no DHCP running, but that is exactly what ICS
does - it is a self-contained DHCP server. Also, check your firewall
software and/or router. If you are allowing inbound, you DO have a
firewall, don't you??

 

[Alder]

Thanks serverguy,

The reference to DHCP and DNS servers was there because I noticed other
posts here where folks had non-ICS DHCP and/or DNS servers running and
the advise given in response was against doing so. I simply wanted to
assure the kind folks here that this was not the problem.

Similarly, I avoided any reference to a firewall because in trying to
troubleshoot the blocking of inbound connections I disabled it without
effect. That, combined with the first point, seemed to point to ICS and
ay services it depends on, as the cause.

For the record, I run ZA Pro on the ICS host. The two ICS clients
operate without firewalls.

My suspicion is that I've disabled a service necessary for the proper
functioning of ICS. The ICS service itself is set to Automatic and is
Started, but if someone could post a list of other services that ICS
depends on, I'd appreciate it.

Thanks,

Terry