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Disconnect if signal drops under -75 dB
Posted: Wed Dec 13, 2017 12:16 pm
by korg
Hi,
i have put this code to wireless tables - access list but it does not seem to work. I wanted to setup 'if the signal drops under -75 then this client should disconnect from wlan'.
Any other suggestion?
tx
korg
Re: Disconnect if signal drops under -75 dB
Posted: Wed Dec 13, 2017 2:42 pm
by AlainCasault
Hello Korg,
I've never tried the way you did it in your 1st entry, but that field is a range. "Lowest accepted" to "highest accepted" RSSI.
-75dBm is what?? Lowest, highest? Your router doesn't know. You should write -75..-30, for example. It'll refuse clients that are lower or higher than those numbers.
I'm guessing your 2nd example is to kick out clients with low signal, but you don't need to do it if your 1st entry works. Don't forget to uncheck "Default authenticate" in your wlan interface parameters to enforce the use of your access list entries.
Ciao,
AC
Re: Disconnect if signal drops under -75 dB
Posted: Wed Dec 13, 2017 7:00 pm
by korg
Thank you, its working. So, no default authentication and Access list with those entries...
great
korg
Re: Disconnect if signal drops under -75 dB
Posted: Thu Dec 14, 2017 1:15 am
by Petri
@Korg Are you aware that the configuration does not do what you asked in your first post (and title)? The access list only affects connecting clients. After the client is connected it won't be disconnected even if the signal drops below the threshold. If the client gets disconnected, he won't be allowed back, though.
Re: Disconnect if signal drops under -75 dB
Posted: Thu Dec 14, 2017 3:55 am
by AlainCasault
@Korg Are you aware that the configuration does not do what you asked in your first post (and title)? The access list only affects connecting clients. After the client is connected it won't be disconnected even if the signal drops below the threshold. If the client gets disconnected, he won't be allowed back, though.
Hello Petri,
I re-read
https://wiki.mikrotik.com/wiki/Manual:I ... ccess_List and I must agree with you on this. It is written that AP checks as STA connects. But!!!
I just made some test with a range of -45..0 and when I place a metal box over my client, it gets kicked out because of weak signal. I changed the access-list to -120..0 and the STA stays on (RSSI about -60dBm).
Also, I read this:
signal-range (NUM..NUM - both NUM are numbers in the range -120..120; Default: -120..120)
Rule matches if signal strength of the station is within the range.
If signal strength of the station will go out of the range that is specified in the rule, access point will disconnect that station.
Which leads me to think that it's for connected clients also.
And looking at the logs, it's not as if the client left and came back. I never left the AP.
Regards,
Re: Disconnect if signal drops under -75 dB
Posted: Thu Dec 14, 2017 2:21 pm
by Petri
Apparently I stand corrected. Live and learn
The wiki page also contains this example stating clearly that the client will be disconnected:
For example, if client's signal during connection is -41 and we have ACL rule
/interface wireless access-list
add authentication=yes forwarding=yes interface=wlan2 signal-range=-55..0
Then connection is not matched to any ACL rule and if signal drops to -70..-80, client will not be disconnected.
To make it work correctly it is required that client is matched by any of ACL rules.
If we modify ACL rules in previous example to:
/interface wireless access-list
add interface=wlan2 signal-range=-55
add authentication=no forwarding=no interface=wlan2 signal-range=-120..-56
Then if signal drops to -56, client will be disconnected.
The authentication=no part is the most misleading part. Authentication happens when the client connects, not during the connection. I do think it is more useful this way, however.
Re: Disconnect if signal drops under -75 dB
Posted: Thu Dec 14, 2017 5:07 pm
by AlainCasault
I think that page has some errors.
For example, if client's signal during connection is -41 and we have ACL rule
/interface wireless access-list
add authentication=yes forwarding=yes interface=wlan2 signal-range=-55..0
Then connection is not matched to any ACL rule ....
Unless I forgot everything my Math teacher showed me, -41 IS within the -55 to 0 range, so it WILL match. It think they got it mixed up with
add interface=wlan2 signal-range=-55
Now THAT would NOT match -41. And I'm very surprised they give this as an example since that field is supposed to be a range. But I haven't tested that yet.
I agree with you on the authentication=no part. I like to use it on my kids when I'm angry at them...
Best regards,
Re: Disconnect if signal drops under -75 dB
Posted: Thu Dec 14, 2017 9:00 pm
by Petri
I think the page is mostly correct. It needs only slight rephrasing.
I believe the author meant that the -41dBm signal IS matched by the rule, but there is no rule to apply if the signal drops - assuming the default is to authenticate. In the second example there is a rule to NOT authenticate -120...-56dBm clients.
The text could be improved by just removing the AND:
Then connection is not matched to any ACL rule and if signal drops to -70..-80, client will not be disconnected.
(I just wasn't aware this is applied to already connected clients as well.)