View Full Version : Vraag: 3 different routers...same problem...

6 augustus 2009, 20:23
Dear all,

my apologies for writing in English but my Dutch is not (yet!) good enough for explaining my internet problems with Ziggo in detail...

As far as I understand from the different postings here, many people share my problem that the internet connection is disrupted regularly when using a router together with the Ziggo Motorola modem. I used to have some disruptions from time to time but the intervals are in the range of minutes in the meantime what is definitively a bit too much...

I read explanations about problems with the lease-time of the Ziggo DHCP server and that _some_ routers may have problems due to wrong handling of the DHCP signals, resulting in the described disruptions.

I also read the hint to set the DNS servers of the router to the OpenDNS servers.

In the meantime I tried 3 different routers (Siemens Gigaset SE551, Linksys WRT320N, Sitecom WL-540) and there is no difference at all in their behaviour. This is strange especially for the Sitecom router as this one was delivered together with the All-in-One package by Casema.

When connecting the PC directly to the Motorola modem the connection is stable of course...

Do you have any hint for me before I go nuts?

Thanks a lot in advance!


6 augustus 2009, 22:25
What we need from you first, is an indication about what causes the disruption.
Could you try to reproduce the modem and the router logfiles (you might have to turn router logging on to start with).

Signal levels, signal to noise ratio, correctable and uncorrectable codewords would be nice too, just to get an idea about how good/marginal your connection situation really is.

Mees de Roo

7 augustus 2009, 00:56
Thank you very much for the fast reply!
You even seem to have solved the problem just by asking for logfiles :)

Following your suggestion to copy the logfiles of the router and the modem I started investigating how the modem does store its logfiles and I found out that I can actually log-in to the modem. A fact the manual is completely silent about...shame on me for noticing this that late...

Browsing through the options I noticed that the modem has a DHCP server of its own that was probably assigning IP addresses in competition with my router. Disabling the DHCP server of the modem gave me a - so far - excellently stable connection from all my PCs to the internet :)

What confuses me a bit is that it worked for quite some time without any this internal DHCP server in the modem maybe a feature that was added/activated just recently in an automatic firmware update? made my day! :applause:


7 augustus 2009, 12:55
I'm glad to have provided (at least a temporary) solution for your problems. However, you should read the modem information on DHCP carefully. It states that this DHCP is operational only under the condition that an external (bridged) connection with the cable is absent!
This means that this DHCP enabling/disabling can only affect your router connection, when your modem looses connection with the cable (possibly for only a very short period) and regains it immediately after.
The router(s) cannot handle two DHCP requests in a row and get stuck; your PC(s) do not mind.
The usual cause for loosing DHCP is the router failing to renew halfway its allotted lease-time, leaving it to the DHCP server to drop the connection. Given your repeat-time of minutes that is not a likely scenario.
Hence my request for your (modem and router) logfiles; I hoped to get some information from them about a fluttering connection/signals/signal to noise ratio or whatever.

Mees de Roo