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New Visitor
Posts: 2
Registered: ‎11-04-2003

router won't auto renew and release ip address

After using router successfully for months and months, last night I couldn't get a connection. Connecting directly to the cable modem worked, so on my Linksys router, I went to the admin page at http://192.168.1.1, and clicked ip address renew and then release. That fixed it. Why didn't it do that automatically after I cycled the power on everything multiple times? It wouldn't be a problem, but I also use another router supplied by my work, and I can't get to that router's admin page because my work put a password on it. Any ideas?
Networking Expert
Baric
Posts: 24,238
Registered: ‎07-28-2003

Re: router won't auto renew and release ip address

It sounds to me like the router and Comcast somehow got out of sync on DHCP lease timeout. If the router thinks it has a valid lease that has yet to expire, there is no reason for it to try renewing the lease.

If this is a one time occurence, I would just forget about it. If it happens again, then I'd update the router's firmware and perform a factory reset and reconfigure it. As for the work router, since it's protected by your work IT depeartment, just give it to them to fix, it's not your concern unless you want to break into it.
New Visitor
Posts: 2
Registered: ‎11-04-2003

Re: router won't auto renew and release ip address

Thanks. As long as I have your ear (or your eyes), is there any way to trick a router into getting a new ip address, short of going through the admin page? I'm talking about the work router now. (side note: the wireless work router was the one that stopped working, so I replaced it with my old non-wireless one, and it didn't work either, until I did the renew/release) Cycling the power didn't work, but maybe there's some specific order I didn't follow? Or can I chain the routers together somehow, so that the work router connects through the old router I have gotten to work. I realize your advice about letting my work network guys fix it is the right advice, this is more for my general knowledge - I'd like to understand how these things work a little better. What could Comcast have done in the last 24 hours that would have made things get out of sync? Does it have something to do with that letter I got saying no more multiple ip addresses (which I shouldn't have had anyway)? How long are these leases typically - will it fix itself after that out-of-sync lease expires on the router?

Again, thanks for your quick reply.
Networking Expert
Baric
Posts: 24,238
Registered: ‎07-28-2003

Re: router won't auto renew and release ip address

Anonymous said:
is there any way to trick a router into getting a new ip address, short of going through the admin page?

Depends on the router. With some, they will renew their lease on powerup, irregardless of when the expiration time is ont he current lease. Some routers don't even save the lease in static or non-volitile memory so that a reboot looses this information altogehter and they HAVE to get another lease. Most will renew on power up, I think.

Cycling the power didn't work, but maybe there's some specific order I didn't follow?

That should have worked. But always do things in this order. Pwer everything down, power up the cable modem and allow it to connect, piwer up the router and let it initialize, then power up your systems.

Or can I chain the routers together somehow, so that the work router connects through the old router I have gotten to work

hehe...no need to get quite so Draconian about things. The router should automatically renew it's lease when half the lease time has expired. If it's not, then there is something wrong with the router and it needs to be fixed. Firware upgrade and reset usually fixes these types of problem. It's not unknown for a router to have a problem due to a corrupted firmware load or messed up settings.

I realize your advice about letting my work network guys fix it is the right advice, this is more for my general knowledge - I'd like to understand how these things work a little better.

Always a good idea to understand basically how things work. No arguments here.

What could Comcast have done in the last 24 hours that would have made things get out of sync?

Probably nothing. I epxect this is a one time hiccup and hte issue is just as likely to be local as with Comcast. Unless it's a reoccuring theme, it's nothing to worry about.

Does it have something to do with that letter I got saying no more multiple ip addresses (which I shouldn't have had anyway)?

Probably not, that letter means youa re connecting different devices to your modem which might be an indication that you will have FUTURE problems when they implement the upcoming measures (which used to exist and Comcast screwed up about the time they took over from ATTBI and during the recent speed upgrade). As long as you are not direct connecting more than one deivce at a time and are power cycleing the modem after switching devices, you should be fine.

How long are these leases typically - will it fix itself after that out-of-sync lease expires on the router?

Depends on your area, seems like most ex-ATTBI areas are 4 days, and many legacy Comcast areas are 7 days. That means leases will renew every 2 days and 3.5 days, respectively.