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join:2006-08-20

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Possible DHCP Problem on Fiber?

Hi Everyone,

Back in the summer we signed up for high speed 25 here in Salmon Arm on fibre. I have the ONT connected to my own router (Asus RT-N16 running Tomato).

I've "lost" internet connectivity twice since getting setup. Once a few months, and again earlier this morning. To get internet connectivity working again, all I did each time was release and renew the WAN IP address on the router. Both times this fixed the problem immediately, and I was also issued a new IP address.

I read in this thread »Opik IP address lease time that the IP address lease time is 4 hours. Yet when I look in my router status page, it comes up as 24 hours.

Could my router somehow be thinking the lease time is wrong, and not asking for a renewal at the right time? Thus I lose Internet access until I force a renewal?

Any thoughts?

Thanks.
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Just one more thing to add. Both times that I had to "force" a DHCP renewal, I received a new IP address from Telus. The one that I had been using previously (sometimes for a month or two), I isn't reissued.

This makes me think that Telus wants to give me a new IP address, but can't because my router hasn't asked for DHCP renewal in a timely manner.
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Edit: Duplicate Post

pfak
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join:2002-12-29
Vancouver, BC

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TELUS doesn't properly handle DHCP lease times when they are doing network maintenance. They should drop the lease time more drastically when they're changing subnets for a particular segment. Your router will ask for a new lease sometime within the DHCP lease period specified by TELUS, but until then you won't have Internet access. There's nothing wrong with your router.
couttsj
join:2010-07-29
Vernon, BC

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To understand your issue, you need to understand how DHCP works. Using command access on my router:
----------------------------------------------------
> ip dhcp enif1 stat
DHCP on iface enif1 is client
Hostname :
Domain Name :
Server IP address: 173.182.207.20
Client IP address: 206.116.175.136/21
DNS server : 75.153.176.9, 75.153.176.1
Default gateway: 206.116.168.1
Lease time : 86400 seconds
Renewal time: 43199 seconds
Rebind time : 75599 seconds
Client State = 3, retry = 2
periodtimer = 12972437, timer = 29824
flags = 2
Status:
Packet InCount: 138, OutCount: 137, DiscardCount: 0
----------------------------------------------------
Your computer broadcasts a DHCP request to any DHCP servers on the network. The first server to send a response assigns the various parameters to the requester, and it is usually stored on server indexed with the MAC address of the requester. From the above, the lease time is 23.9 hours, and the rebind time is 21 hours. The renewal time is 12 hours, but your router will usually renew in less time than that. If, for any reason, connectivity is lost during the renewal cycle, the lease could expire and the present assignment will be lost. This happens to us during an extended power outage, or when Telus takes down a server for maintenance, but there could be a number of other issues including equipment failure.
encircle
join:2006-08-20

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Thanks for the info, sounds like it's more of a Telus issue rather than my setup.

Hopefully it won't occur too often.
bb147
join:2005-04-05
BC, Canada

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Member

Just had this exact same issue here! A release/renew on the router fixed it.

Somewhat annoying.