I don't know if this is the best spot to post this, but it seemed to fit the best to me.
A family member just got a desktop Mac and it's currently using the WiFi off of my router. I use a 2Wire Homeportal 1000HW, which is my DSL modem as well as router, and includes Ethernet, WiFi, and phoneline connection options (the last of which I don't use).
Ever since this computer was connected, it's been trying to connect to my computer which I've blocked with my firewall. According to Comodo, it's trying to access "System" on Source Port 55472 (that's just the latest port, it seems to use the whole 54000-55000 range), and always with the destination port 139. In the last 15 minutes it's tried to connect more than 25 times.
I can't fathom why it would be trying to connect to my computer as they are completely separate, and do not share any devices or anything like that. They're just connected to the same router. I've had a Mac Laptop connected to this WiFi before and it never did this.
Is there anyway I can stop it from making these access attempts?
First I am not familiar with MAC's. Port 139 NetBios is used for windows file and printer sharing and is one of the most commonly scanned ports on a remote machine. Your source is coming from the MAC, not a port scanner that might have other ideas.
Check to see if file sharing is on in the MAC as it is possible to have network shares between the MAC and Windows machine http://lifehacker.com/software/mac-os-x/ho…r-pc-247541.php
Alternately if your firewall is eating the packets, then you could just leave as is also.
I just checked the Mac, and it doesn't even have a "Windows Sharing" option under the sharing window. All sharing options are and have been disabled. I did change one thing though, which was on the Network settings. It had a check box to "ask to join a new network" or join automatically. It was set to auto, so I set it to ask. I doubt that will fix it though.
More than anything this thing is an annoyance. I really like to keep an eye on my firewalls reports of what it's had to block. But since I get over 100 blocks per hour from this thing, it generally pushes anything that might be of real interest out of the logs.
I don't have my Mac in front of me, but…
Go to the system settings on OS X, go to networks, find the options for the wireless device, and untick the file and printer sharing box. Or block it.
Macs like to snoop around the network for open fileshares, and this is what it's doing. It's not really harmful, unless you have something sitting in one that you don't want to be discovered, and that wouldn't be very smart.
Based on that thread, I downloaded and installed Waterroof on the mac, and wrote a few rules that blocked that activity. Since then I've not had any connection attempts being blocked by my firewall.
I have to admit though that it would be nice if you could just disable those attempts to begin with on the mac, rather than just switching whose firewall is doing the blocking. At least this will keep it from flooding my log files making me miss something potentially important.
