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TheSirStumfy
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DHCP issue

Mon Nov 12, 2018 9:42 pm

Hello,

i have a strange issue where devices connected to the router sometimes switch DHCP network to the gateway from the ISP router.

A device on the MT router would be on xx.xx.88.1 gateway, than just after a disconnect and reconnect it would jump to IPS gateway of xx.xx.1.1, but trough the same WiFi network defined on the mikrotik router.

Any idea what would cause this or an easy way to prevent devices jumping on any other DHCP than the MikroTik defined ones?

Regards.
 
anav
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Re: DHCP issue

Mon Nov 12, 2018 9:44 pm

Post config
I'd rather manage rats than software. Follow my advice at your own risk! (Sob & mkx forced me to write that!)
 
TheSirStumfy
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Re: DHCP issue

Mon Nov 12, 2018 9:45 pm

What part of config would you like?
 
anav
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Re: DHCP issue

Mon Nov 12, 2018 10:47 pm

THe Whole Thing LOL less passwords and indentifying info on your WAN, like WANIP or WAN gateway.
but use the code quotations in the upper bar
I'd rather manage rats than software. Follow my advice at your own risk! (Sob & mkx forced me to write that!)
 
lambert
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Re: DHCP issue  [SOLVED]

Tue Nov 13, 2018 12:50 am

The two things which are most likely are:

1 ) Your WAN interface is bridged with your LAN.

2 ) Your ISP's WiFi has the same SSID/password configured and your devices are sometimes connecting to it directly.

With the config, we'll know.
 
TheSirStumfy
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Re: DHCP issue

Tue Nov 13, 2018 9:03 am

The config is very long and includes a lot of info id not put on the internet, is there really not a specific section to post?

Also yes i was thinking it could be the ISP router. Problem is this is an "inherited" network from previous admin, so i need to dig up the router pwd somehow, to check whats going on there.
 
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Steveocee
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Re: DHCP issue

Tue Nov 13, 2018 9:24 am

It sounds like there is a second DHCP server on your network. Maybe you have bridged the WAN interface? Could be a possibility.

Try turning off your dhcp server and then connect to your network as dhcp client to check.

Also posting config is needed with most problems, 95% of it will not be unique to you but there is a “hide-sensitive” option to remove details that identify. It’s fairly common and allows the “nerds” to fault find your router without giving access to it.
Steve "Steveocee" Carter
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My Website - My MikroTik Tutorials
 
TheSirStumfy
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Re: DHCP issue

Tue Nov 13, 2018 10:19 am

The ether1 where the ISP is does not seem to be bridged.
Capture.JPG
I understand there is a hide sensitive export, but still it has many external IP addresses for VPN, OVPN client names, SSIDs etc... Still a bit too sensitive for internet.
You do not have the required permissions to view the files attached to this post.
 
nescafe2002
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Re: DHCP issue

Tue Nov 13, 2018 11:10 am

You can set up a DHCP Alert to detect other dhcp servers on your network.

IP > DHCP Server > Alerts

Set up an alert on your local network interface.

Check the log for DHCP error events.

https://wiki.mikrotik.com/wiki/Manual:I ... ver#Alerts
 
TheSirStumfy
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Re: DHCP issue

Tue Nov 13, 2018 11:40 am

I would like to thank everyone for the help.

the issue was in fact that the ISP router was set to the same SSID and pwd as the Mikrotik.

This of course made devices wander around.

Regards.

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