GRC shields up - closed but visible ports

[smithy]

Hi,

Is it possible on AC86U to stop response from my router on ports:

135
137
138
139
445

 

[smithy]

hi, realised i posted in wrong forum, can a mod move to general asus router forum? thank you

 

[ColinTaylor]

Hi,

Is it possible on AC86U to stop response from my router on ports:

135
137
138
139
445

No, because those ports are being intercepted and responded to by your ISP. The packets never get as far as your router.

 

[OzarkEdge]

No, because those ports are being intercepted and responded to by your ISP. The packets never get as far as your router.

I have a similar intermittent issue with port 0 that has been puzzling me. Do you know why my ISP would intercept and respond for port 0?

OE

 

[ColinTaylor]

I have a similar intermittent issue with port 0 that has been puzzling me. Do you know why my ISP would intercept and respond for port 0?

As far as I know port 0 is not a valid port and cannot be used per se. However, my understanding is that a host can use port 0 to bind to a free dynamic port (49152-65535). But this later point should have no bearing on your port scanning result.

EDIT: In other words, I have no idea why you are seeing inconsistent results on port 0. Maybe it just depends on which of your ISP's routers you're hitting when you do the scan.

 

[cooloutac]

I have a similar intermittent issue with port 0 that has been puzzling me. Do you know why my ISP would intercept and respond for port 0?

OE

probably for security reasons.

 

[RMerlin]

EDIT: In other words, I have no idea why you are seeing inconsistent results on port 0. Maybe it just depends on which of your ISP's routers you're hitting when you do the scan.

Or maybe because the scanning tool itself isn`t properly scanning port 0. An application that tries to bind to port 0 will typically get allocated a random free port (this behaviour may vary between operating systems). So there`s a good chance that the scanner is in reality scanning a totally random port when it tries to scan for port 0.

 

[ColinTaylor]

Or maybe because the scanning tool itself isn`t properly scanning port 0. An application that tries to bind to port 0 will typically get allocated a random free port (this behaviour may vary between operating systems). So there`s a good chance that the scanner is in reality scanning a totally random port when it tries to scan for port 0.

I thought about that but looking at the packet captures on my router it's only the destination port would be set to 0. The source port (which is what the scanner will be binding to) is a standard ephemeral port.