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I have a router(DLink) that broadcasts at both 2.4 GHz and 5 GHz. I wish to set up a filter such that all devices other than phones and tablets should connect to it. How can I do this? I'm not sure about MAC address filtering as I can change MAC addresses on most of my devices.

UPDATE

I did a little research on this, for those who might want to pick up from here.

It is hard to determine the type of device running in a network, primarily because the device might not want to give up details that could potentially compromise its security. One way is to run a script on the router to detect the type of OS running on the host.

Tools like nmap come in handy. It can create a fingerprint of the device and match against in its database. This needs at least one open port to detect the OS successfully. 99% of desktops/PCs that I tested on gave the right answer. Mobile devices made an abominably poor performance, nmap couldn't detect even a single device. This of course, could be because most devices have all the 1000 scanned ports closed. This is definitely harder to spoof and certainly better than MAC based filtering.

Remote OS detection is detailed here.

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  • If someone can change their MAC address, do you think they couldn't change the "phone/tablet/PC" indication, if there was one?
    – user1686
    Oct 12 '16 at 11:21
  • @grawity I'm hoping they can't. Oct 12 '16 at 11:25
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    That's the problem, though – 1) there isn't any such indication, and 2) even if there was, someone would just find ways to change it, because that's... really not something that can possibly be useful for security purposes.
    – user1686
    Oct 12 '16 at 11:30
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    Yes, I'm saying it is impossible.
    – user1686
    Oct 12 '16 at 11:39
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    MAC filtering is not secure, Djack, because you can change a device's MAC address
    – Rory Alsop
    Oct 12 '16 at 12:53
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You cannot make a configuration to comply with such a rule.

But you can open the router web interface and go to Advanced tab along the top and then on Network Filter.

Put MAC Filtering ON and ALLOW listed computers to access the network. the rest will be implicitly denied.

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  • How am I supposed to know which PCs will connect to it in the future? Oct 12 '16 at 11:25
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    @Djack You'll know because if they want to attach they'll have to ask you to add them to the whitelist. At which point you can turn of the filtering, let them connect, add their MAC to the whitelist, and turn it back on. Oct 12 '16 at 12:18
  • Yes, and some firmware versions make it easier and show the connection attempts too, so you will be able to add them directly.
    – Overmind
    Oct 12 '16 at 12:33
  • @Ƭᴇcʜιᴇ007 No. The point of this is to automate the exercise. Oct 13 '16 at 9:19
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    Wildcards seems are not supported even in DDWRT. This got no answer yet. dd-wrt.com/phpBB2/…
    – Overmind
    Oct 17 '16 at 12:34

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