Hi Group: I've tested for open ports from all the LAN clients behind my linux box router/gateway/firewall and all of them come up with the same results: port 21, 23, and 80 are open according to the results of the Steve Gibson Shields Up test. I can't figure out how this can be happening. I've run a full nmap -P0 (that's a zero) on all my local ip addresses - 192.168.169.* You'll see below that the only ports open according to nmap on all the clients is Port 139. This is appropriate as the box on 192.168.169.2 is running a Samba server that all the clients connect to. The box on 192.168.169.2 has Port 80 open because I run Apache as an intranet webserver. It cannot be accessed from outside the firewall. Port 631 is open because that's the port that receives print jobs via the CUPS printserver. The LAN clients send print jobs to the printserver via port 631. Lastly, I had the X window system up and running when I ran nmap so you can see a port open for that. But none of the clients, nor the gateway address on the routerbox (192.168.169.1) show port 21, 23, and 80 as open. So, I'm left with some questions: A) Is the Gibson test accurate or am I misunderstanding the results? B) Do I need to do another kind of diagnostic test using nmap? Thank you for reading the long post. I appreciate the time and help. Mike Starting nmap 3.55 ( http://www.insecure.org/nmap/ ) at 2004-09-09 10:21 EDT All 1660 scanned ports on 192.168.169.0 are: filtered All 1660 scanned ports on 192.168.169.1 are: filtered Interesting ports on primary.us (192.168.169.2): (The 1655 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 80/tcp open http 139/tcp open netbios-ssn 631/tcp open ipp 6000/tcp open X11 Interesting ports on 192.168.169.3: (The 1659 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 139/tcp open netbios-ssn MAC Address: XXXXXXXXXXXXXXXX (Intel) Interesting ports on 192.168.169.4: (The 1658 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 135/tcp open msrpc 139/tcp open netbios-ssn MAC Address: XXXXXXXXXXXXXX (3com) Interesting ports on 192.168.169.5: (The 1659 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 139/tcp open netbios-ssn MAC Address: XXXXXXXXXXXXXXXXXX (Netgear) Interesting ports on 192.168.169.6: (The 1659 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 139/tcp open netbios-ssn MAC Address: XXXXXXXXXXXXXXX (The Linksys Group) Interesting ports on 192.168.169.7: (The 1659 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 139/tcp open netbios-ssn MAC Address: XXXXXXXXXXXXXXXX (3com) All 1660 scanned ports on 192.168.169.8 are: filtered Interesting ports on 192.168.169.9: (The 1659 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 139/tcp open netbios-ssn MAC Address: XXXXXXXXXXXXXXXX (Hsing TECH. Enterprise CO.) Interesting ports on 192.168.169.10: (The 1659 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 139/tcp open netbios-ssn MAC Address: XXXXXXXXXXXXXXXXXX (Hsing TECH. Enterprise CO.) All 1660 scanned ports on 192.168.169.11 are: filtered All 1660 scanned ports on 192.168.169.12 are: filtered Interesting ports on 192.168.169.13: (The 1659 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 139/tcp open netbios-ssn MAC Address: XXXXXXXXXXXXXXX (Micro-star International CO.) Interesting ports on 192.168.169.14: (The 1658 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 135/tcp open msrpc 139/tcp open netbios-ssn MAC Address: XXXXXXXXXXXXXXXXXXX (The Linksys Group) Interesting ports on 192.168.169.15: (The 1659 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 139/tcp open netbios-ssn MAC Address: XXXXXXXXXXXXXXX (Intel - Hf1-06) Interesting ports on 192.168.169.16: (The 1659 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 139/tcp open netbios-ssn MAC Address: XXXXXXXXXXXXXXXXX (Micro-star International CO.) Interesting ports on 192.168.169.17: (The 1659 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 139/tcp open netbios-ssn MAC Address: XXXXXXXXXXXXXXXXX (Micro-star International CO.) Interesting ports on 192.168.169.18: (The 1659 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 139/tcp open netbios-ssn MAC Address: XXXXXXXXXXXXXXXXXXXX (Micro-star International CO.) Interesting ports on 192.168.169.19: (The 1659 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 139/tcp open netbios-ssn MAC Address: XXXXXXXXXXXXXX (Micro-star International CO.) Interesting ports on 192.168.169.20: (The 1659 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 139/tcp open netbios-ssn MAC Address: XXXXXXXXXXXXXXX (Micro-star International CO.) All 1660 scanned ports on 192.168.169.21 are: filtered Interesting ports on 192.168.169.22: (The 1659 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 139/tcp open netbios-ssn MAC Address: XXXXXXXXXXXX (Micro-star International CO.) All 1660 scanned ports on 192.168.169.23 are: filtered All 1660 scanned ports on 192.168.169.24 are: filtered -----------<<<snip>>>-------------------------