Topic 'DHCP address has stayed the same for the past 1+ month' in forum 'RCN' - dslreports.com http://www.dslreports.com/forum/DHCP-address-has-stayed-the-same-for-the-past-1-month-27708723 en Wed, 19 Jun 2013 03:08:46 EDT Wed, 19 Jun 2013 03:08:46 EDT Re: DHCP address has stayed the same for the past 1+ month http://www.dslreports.com/forum/Re-DHCP-address-has-stayed-the-same-for-the-past-1-month-27717162
If you're that worried about your IP, just get a static IP. I know it's an extra $10/month, but you can then guarantee your IP won't ever change and you won't need DynDNS. I'm not sure if this server is for work or for play but there's no reason why if it's for work you don't have the static IP. If it's for play, there's no reason why the extremely rare IP change would matter. The only time my IP changed in the multiple years i've been with RCN was when I moved two cities over.

DNS changes very quick now a days... the up to 24 hours change is something I haven't seen in a long long time when I change DNS.]]> http://www.dslreports.com/forum/Re-DHCP-address-has-stayed-the-same-for-the-past-1-month-27717162 Sun, 11 Nov 2012 14:32:51 EDT Re: DHCP address has stayed the same for the past 1+ month http://www.dslreports.com/forum/Re-DHCP-address-has-stayed-the-same-for-the-past-1-month-27717106 said by cchhat01:

I've got a ddns script running on my router behind the modem which basically updates my IP with the ddns provider noip.com.

The problem is with your script. DynDNS service is similar to NoIP. They state clearly the update client needs to resend the same IP if it hasn't changed in 28 days in order to avoid the record being deleted. I suspect NoIP is the same.

Your script needs to be modified to check if the IP hasn't changed in the past 28 (or similar) days, and send the update record with the same address if this is the case.

Pretty standard stuff...

I think it's been a number of YEARS since my IP has changed...]]> http://www.dslreports.com/forum/Re-DHCP-address-has-stayed-the-same-for-the-past-1-month-27717106 Sun, 11 Nov 2012 14:06:17 EDT Re: DHCP address has stayed the same for the past 1+ month http://www.dslreports.com/forum/Re-DHCP-address-has-stayed-the-same-for-the-past-1-month-27716836
When you're leased an IP by DHCP, unless a specific rule is set to not lease the same IP, the DHCP server will always give the same IP out again. It'll also actually start the renew process halfway through your lease time. Example, if you have a 4 day lease, it'll actually renew it in 2 days (or attempt to anyway).

That said... it's actually in RCN's best interest not to mess around with settings and make changes to the IP address. There's no reason too and if they added special rules it just makes for something else to go wrong.]]> http://www.dslreports.com/forum/Re-DHCP-address-has-stayed-the-same-for-the-past-1-month-27716836 Sun, 11 Nov 2012 12:14:40 EDT Re: DHCP address has stayed the same for the past 1+ month http://www.dslreports.com/forum/Re-DHCP-address-has-stayed-the-same-for-the-past-1-month-27716718 said by cchhat01:

And why do I need to finagle with my mac address to obtain a new IP. This is DHCP. This is what I would have expected from other cable internet providers as well.

DHCP = Dynamic Host Configuration Protocol.
In no way does that indicate you would get a new IP address every time your lease expires. Since moving from an RCN serviced area about a year and a half ago and switching to Comcast and presently to FiOS, I've had exactly 2 IPs (one Comcast and one Verizon). My IP lease was 3 days with Comcast and 7 days with Verizon each and every renew reassigned the same IP I already had leased.

And why should RCN have to finagle DHCP for you to obtain a new IP?
As I said, since moving from RCN to other large providers, I see the same pattern of retaining the same dynamic IP indefinitely. ]]> http://www.dslreports.com/forum/Re-DHCP-address-has-stayed-the-same-for-the-past-1-month-27716718 Sun, 11 Nov 2012 11:02:10 EDT Re: DHCP address has stayed the same for the past 1+ month http://www.dslreports.com/forum/Re-DHCP-address-has-stayed-the-same-for-the-past-1-month-27713169 said by negativeduck:

Not to challenge Joe but this is not the preferred way. There is no reason for your IP address to change if we don't need to and really it's a dumb policy to delete a record if it doesn't change. Is it that your IP hasn't changed or is that you haven't sent a record update in X time. I would suggest sending an updated transaction to them every couple days even if it's a repeat of what you already have. and see if that helps you.

My router sends a record update to the ddns provider every 1 hour.
I can guarantee this is working because the same model router with identical software (OpenWRT) is configured in a similar way to update a dns record from another provider (sitting all the way in India). The other provider changes the ip address upon every pppd renewal.

However in case of my service (RCN), I need to remind myself to login at noip.com and hit the update button. Noip.com does not process an automated update if the IP address has stayed the same, and that is my problem.

And why do I need to finagle with my mac address to obtain a new IP. This is DHCP. This is what I would have expected from other cable internet providers as well.

Thanks.
C
--
"Look at me, I'm Dr. Zoidberg, homeowner."]]> http://www.dslreports.com/forum/Re-DHCP-address-has-stayed-the-same-for-the-past-1-month-27713169 Fri, 09 Nov 2012 20:02:34 EDT Re: DHCP address has stayed the same for the past 1+ month http://www.dslreports.com/forum/Re-DHCP-address-has-stayed-the-same-for-the-past-1-month-27710106 --
Bryan Laird
RCN Engineering]]> http://www.dslreports.com/forum/Re-DHCP-address-has-stayed-the-same-for-the-past-1-month-27710106 Fri, 09 Nov 2012 07:16:30 EDT Re: DHCP address has stayed the same for the past 1+ month http://www.dslreports.com/forum/Re-DHCP-address-has-stayed-the-same-for-the-past-1-month-27710031 --
Joe Mirabella
VOD Operations]]> http://www.dslreports.com/forum/Re-DHCP-address-has-stayed-the-same-for-the-past-1-month-27710031 Fri, 09 Nov 2012 06:04:00 EDT Re: DHCP address has stayed the same for the past 1+ month http://www.dslreports.com/forum/Re-DHCP-address-has-stayed-the-same-for-the-past-1-month-27709060
What had me ever MORE surprised is after Sandy, we had a 6 days power outage and when my modem came back online I plugged in my laptop to test out a few things and got an IP. Plugged in my router (same since Jan 2011) and rebooted the modem and got the SAME IP even after days without power!! I figured my IP address would have been gone by now since other people had power and the DHCP lease was only 2 days. :o]]> http://www.dslreports.com/forum/Re-DHCP-address-has-stayed-the-same-for-the-past-1-month-27709060 Thu, 08 Nov 2012 19:58:11 EDT DHCP address has stayed the same for the past 1+ month http://www.dslreports.com/forum/DHCP-address-has-stayed-the-same-for-the-past-1-month-27708723
I'm subscribed to RCN Cable Internet for sometime now.
I've got a Linksys Cable modem which I bought really cheap from Newegg.com when they were selling it for about $20 few years back and its been working great (fingers crossed).

I believe my connection is not that it provides a static IP address. It is most probably DHCP because i remember my IP address changing every now and then.
However for the past 1.5 months my IP address hasn't changed.

I've got a ddns script running on my router behind the modem which basically updates my IP with the ddns provider noip.com. However a couple of days back, they sent an email in which they stated that my public IP hasn't changed and that if it doesn't change within a 30 day period, I will lose the ddns hostname.

Basically, I find it strange that my IP address hasn't changed for well over a month when I'm expecting this to change almost every 1-2 weeks. Am I setup for a Static IP or something?

Can someone help me with this?

Also, if this is how RCN works, can someone suggest a free ddns provider that won't complain about the 30 days max timeframe for IP address change?

Thanks,
C
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"Look at me, I'm Dr. Zoidberg, homeowner."]]> http://www.dslreports.com/forum/DHCP-address-has-stayed-the-same-for-the-past-1-month-27708723 Thu, 08 Nov 2012 17:02:19 EDT