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Lawsofphysics
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DHCP Lease - timings

I'm hopeful that there is a simple answer to a problem I've been having.

I work from home and sign in via a work VPN (Global Protect) and have had an issue for some time that the same time every day, the VPN would be interrupted I would need to sign back in and re-authenticate. This can be very disruptive in the middle of a meeting, for example. After lots of investigation - home and office - I recently noticed that the time of this is exactly the same time as my DHCP lease renewal.

For information, I have a mesh system (Tenda MW3) attached to the SH3. It appears to be the primary node which has the lease renewal time. I attempted to reset this by changing the time to late night - and I thought I'd cracked it - but it somehow changed again to this morning (a new time) and the reauthentication issue happened again. Has something else triggered the new time?

I have run a fault check and there are no issues. My BQM is below. I can attach upstream/downstream data if helpful. I won't do it unsolicited just yet.

https://www.thinkbroadband.com/broadband/monitoring/quality/share/079ade288efbb65608f291deac98a97516...

Advice and tips gratefully received.

 

Thanks

Kev

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Tudor
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Re: DHCP Lease - timings

You need to read up the Tenda instructions as I assume you have the VM hub in modem mode and the Tenda in router mode. You could set the renew period to say 1 week instead of 1 day or better still give your machine a real fixed IP address so it does not have to use DHCP. 


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Lawsofphysics
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Re: DHCP Lease - timings

Thanks Tudor. I had a feeling I might miss out something useful.

The SH3 isn't in modem mode, but the WiFi is switched off. The Tenda Mesh is in bridge mode.

I did give the lease time to be a shorter time (5 mins I think) in order to reset the lease period but it didn't take effect. I eventually did it by switching of fthe mesh, refreshing the DHCP, then switching the mesh back on late last night. However, it has reset to a morning time, even though I set it for 24 hours. Happy to try a week lease, but it doesn't solve the timing problem.

However, I'm intrigued by the second idea. How can I give it a fixed address? Are there instructions on this site?

Thanks

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legacy1
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Re: DHCP Lease - timings

Use modem mode.

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ravenstar68
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Re: DHCP Lease - timings

I think you're putting 2 and 2 together and getting 5 here.

As long as a device is connected to a network DHCP leases SHOULDN'T time out.

What normally happens is that at around 50% of lease time, a device will request a lease renewal from the device that gave out the lease.  The DHCP server will then normally send back an ACK and all that happens is that the client updates the lease timer.  Admittedly there is a possibility of the DHCP server sending a NACK, but normally that wouldn't happen.

Tim

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Adduxi
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Re: DHCP Lease - timings


@Lawsofphysics wrote:

Thanks Tudor. I had a feeling I might miss out something useful.

The SH3 isn't in modem mode, but the WiFi is switched off. The Tenda Mesh is in bridge mode. <snip>


Why on earth are you not using the Mesh system as your main Router?  Absolutely the Hub should be in Modem mode.  You will find the routing and other aspects of networking are far superior on the Mesh than the ISP supplied router (Hub) 

 

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Lawsofphysics
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Re: DHCP Lease - timings

Thanks for the advice.

 

The answer to the question of why not modem mode is simply because the engineer recommended the current set-up when it was installed. Who am I to question the 'expert' view of the best way to configuring the SH3?

I've been very open that I've not tried to diagnose the problem, but spotted an interesting repeating pattern. I'll try modem mode later when nobody else is using the internet and hopefully that will resolve matters. I'm still intrigued by the question of if/when/how the lease renewal is disrupting the work VPN - it is a coincidence that keeps happening. Maybe that will have to stay an academic question.

Thanks

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Lawsofphysics
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Message 8 of 18
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Re: DHCP Lease - timings

Just to be clear, sorry. The connection to the wifi appears to be stable during the lease renewal time. But the authenticated VPN connection is dropped and I need to re-authenticate. This is the dispruption.

Kev

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Re: DHCP Lease - timings

The Hub router is a basic device the Tenda will be an improvement and be more flexible. Set it up in this sequence.

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Select the first Tenda unit that will be plugged into the Hub and then set it up to be in DHCP & Nat mode, and then disconnect all cables from it and unplug it - switch all the other Tenda's off and unplug them too.

Then put the VM Hub into modem mode ( see:- https://www.virginmedia.com/help/virgin-media-hub-modem-mode ) and wait a few minuutes for the base light to turn magenta/purple (on a Hub3 - but not on a Hub4!) and initialise.

Once it’s in modem mode, the VM hub “MUST” then be powered off. Make sure it’s fully initialised (leave 5 min) and then put in the WAN cable to the VM hub. - NOW… power up the VM hub and you should get a connection after it initialises in a few minutes.

Switch the other tenda's on and use the recommended App to connect other Mesh units to the first one. This order only needs to be done the first time you connect the router to the VM hub.

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John
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I do not work for VM. My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired 2 WiFi,) SH2 in modem mode with Airport Extreme Router +2 Airport Express's. On VIVID200, Talk Anytime Phone, x2 Mobile SIM only iPhones.
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Message 10 of 18
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Re: DHCP Lease - timings

 

@LawsofphysicsWhat speed is your VM connection?

 

 

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