Happy new year all,

I would like to block all traffic on port 443 (https) from some of my computers. However, logmein.com uses port 443 for part of its remote connection and I cannot figure out how to allow traffic only from logmein.com.

Thanks,
Eric

PART 1 of your Question:
I would like to block all traffic on port 443 (https) from some of my computers.

You can easily make a rule. On the left click security/ then the rules tab and add rule.

The issue is you want PC(x) to use port 443 but not PC(y). It seems you will have to manually assign an IP address to PC(x).
The rules would be

ALLOW PC(x) to ANY Port 443.
BLOCK Internal-Networks to ANY port 443.

If you know the logmein.com IP addresses (which could change at anytime) you could restrict the ANY to logmein.com IP address.
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PART 2 which is probably the answer you are looking for:
However, logmein.com uses port 443 for part of its remote connection and I cannot figure out how to allow traffic only from logmein.com.

Use a static IP for your PC.
Write a rule
ALLOW-AND-FORWARD
SOURCE ANY (or try to restrict to logmein.com)
DESTINATION: THIS GATEWAY
PORT 443
FORWARD to PC(x)

further research shows

U:\>nslookup logmein.com
Server: dhcp1.xxxxx.com
Address: 10.239.231.104

Non-authoritative answer:
Name: logmein.com
Addresses: 77.242.192.60, 69.25.20.64, 74.201.74.60

So you can limit the source to those three IP addresses. 77.242.192.60, 69.25.20.64, 74.201.74.60

Maybe three rules.