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dnoyeB
Ferrous Phallus

join:2000-10-09
Southfield, MI
Reviews:
·Comcast

1 edit
reply to bds85466

Re: ZyXEL PK5001Z Modem dropping exactly every 15 minutes

Im not sure if the Zyxel considers the link lost when the hardware is disconnected of when the IP is gone. If its when the IP is gone, then that explains why the timer is resetting. My guess is that its based on IP. Otherwise it wouldn't be called "IPv4" uptime.

DHCP addresses have an expiration time. Perhaps the DHCP server is giving your device an expiration time of 15 minutes. Maybe you can check with wireshark or something. Based on the log it does not look like its loosing the IP address. Its just renewing it.

Try manually assigning the same IP address to your WAN and see if that stops the cycling. If so, you need to get the DHCP server to quit giving such a small expiration time.

Sorry, I guess that answer is a bit off since you are not using a router but a modem. Still, it looks like the modem is being given a small DHCP lease time. I don't know if that lease time is coming from your ISP, or part of your modem. For me and my cable modem, it comes from the ISP's configuration of my cable modem.

--
dnoyeB

"Then said I, Wisdom [is] better than strength: nevertheless the poor
man's wisdom [is] despised, and his words are not heard. " Ecclesiastes
9:16


bds85466

join:2012-11-17
Waconia, MN

2 edits

said by dnoyeB:

Sorry, I guess that answer is a bit off since you are not using a router but a modem. Still, it looks like the modem is being given a small DHCP lease time. I don't know if that lease time is coming from your ISP, or part of your modem. For me and my cable modem, it comes from the ISP's configuration of my cable modem.

Well to be fair (and to your credit) it is a modem that routes as well....

That was what I was starting to question as well, is this a pre-installed routine to keep uptime to a minimum while idle?...I'm clueless.

Bear with me because I'm completely ignorant when it comes to networking and all the acronyms are starting to blow my mind. Simply a residential customer trying to watch netflix...

So D standing for dynamic, basically DHCP is a way to eliminate the need for static IP's and entering them in? Is my modem 'asking' to join the network (and obtaining a new IP every time)?

Let me see if I can grasp the DHCP handshake correctly:

1. So my modem sends out protocol and asks the DHCP server if it can join the network.

2. The DHCP server then creates potential IP's and other info for the modem (MAC address, LEASE DURATION, etc) sends the info back to the modem.

3. The modem sends acceptance information for one of the IP's and the other info in the packet.

4. The DHCP server sends the actual packet of information to the modem, completing the IP configuration -- using the negotiated parameters including IP and duration.

...if this is correct, I'd say that in most cases, the DHCP server is what dictates the length of the lease, however, it may not be what is causing the problem. The server could be sending out a more lengthy duration, but we might not ever know what the duration is?

The modem still could be acting funky, sending out the "DISCOVER" protocol packet for some odd reason every 15 minutes.

As you point out:

said by dnoyeB:

Based on the log it does not look like its loosing the IP address. Its just renewing it.

said by dnoyeB:

Try manually assigning the same IP address to your WAN and see if that stops the cycling. If so, you need to get the DHCP server to quit giving such a small expiration time.

Though I've never done it before, maybe I will try setting up a static IP for the modem as you suggest? Where would I find that IP to use?