why does my IP address change as often as 10 times a day?

I am curently using NTL as my ISP with a 10mb connection, untill fairly recently I have had no problems, though NTL will only garantee a 3 day lease on an IP address my IP rarely changed (3 times in 12 months) but now I am finding the IP can change as often as 3 times an hour which is realy frustrating when Im trying to host Ventrilo and/or games, I have managed to sort out a dynamic dns address which saves me from having to inform all the users of IP changes but this is still quite annoying for the few minutes it can take for the dydns to catch up.
I have 4 PCs(XP Pro SP2) connected to a Sitecom DC 202 V2 router, NTLhome cable modem (generaly there are only 2PCs online at a time.)
I am fairly sure the problem lies with the router, as yet I have not found a firmware update the I am confident in using (i.e. explained in English) or could this possibly be caused by software/malware?
Any help would be hugely appreciated
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Rob WilliamsCommented:
This is more common with a PPPoE connections. Is that your case?
If it is changing when the connection is idle try enabling the "keep alive" feature on the router. However if PPPoE it may just be your ISP changing policies. I came across one that changes every 20 minutes.
RhinovenomAuthor Commented:
Yes it is a PPPoE connection, having (ranted at) spoken to my ISP they say there is no reason on their side for this to happen as the IP of the modem is fixed for 3 days minimum
Rob WilliamsCommented:
Very odd I have no suggestions I am afraid. I can't see anything on your end forcing a change. The lease time is usually determined by their servers or routers.
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Can you get a static ip from your ISP?
is your modem configurable? ie is it set to connect pppoe as well as your router? if so the two devices could be conflicting... try configuring the modem to a bridge if possible.
RhinovenomAuthor Commented:
I cant get a static IP, and no there is no way to configure the modem its all sorted from the ISPs end.
which device (that you know of) is set to PPPOE? HOW is it configured as the first person (Robwill) asked - what is the keep alive set to?

Do you have AOL installed? ( may need to be configured to connect properly )

Are you using Broadjump (ISP software)?

if your router and the broadjump are both set to PPPOE - you may have multiple PPPOE clients requesting IP's - remove extra PPPOE clients...

RhinovenomAuthor Commented:
Hang on guys, one of the PCs on my network died and have had to wipe it 'n reinstall, fingers crossed, IP hasnt changed since then, so maybe points to some dodgey software my teenage daughter had on her comp, Will let you know
Was the isp sw installed on ur daughters pc? if so, dont put it on again,..could have been multiple pppoe clients.

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RhinovenomAuthor Commented:
Thanks Craig, think you nailed it
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