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Is the WAN IP of an ADSL modem likely to remain the same if it is not rebooted?

Do ISPs change the WAN IP of an ADSL connection while in session (ie. prior to reboot) ?

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Do you mean WAN IP? – MDMarra Jun 16 '10 at 10:38
Yes, corrected. – CJ7 Jun 16 '10 at 10:46
As a benefit for this community, please remember to accept answers to your questions, to avoid wasting the time of those looking to help. – Zayne S Halsall Jun 16 '10 at 11:27
also, posting the same question on two sister sites is considered bad form. – tombull89 Jun 16 '10 at 11:32
@tombull: what 'sister site' have I posted this question to? – CJ7 Jun 16 '10 at 14:26
up vote 3 down vote accepted

Likely, yes. Predictabily, no.

I don't know if they ever change "routinely", but they'll likely change at every line reset, and that'll happen during storms or power outages, just to name a few examples.

Bottom line is, don't rely on the IP to remain the same for any amount of time, but you'll probably be happy when using a service like for the occasional "get back home" connection.

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It varies based on your ISP but you should be prepared for it to change routinely unless you've specifically paid for a service with a static IP.

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how often would the IP address routinely change? – CJ7 Jun 16 '10 at 10:46
totally depends on the ISP; could be every hour, could be never - call your ISP and ask - but as I said you shouldn't bank on IP persistence. – Chopper3 Jun 16 '10 at 11:09
Daily, every 24 hours, is normal. Disconnects you, when the modem reconnects it gets another IP. Sucks if you do FTP at that time. SOme providers allow that to be turned off (and assign you the same IP All the time) for an additional payment (static IP feature - check whether your provider has that). Pure business decision. My cable modem provider does not do that - my prior DSL provider did it. My AVM Fritz can "force" the disconnect to a specific time (i.e. it disconnects itself, makes sure the disconnect happens at a "good" time, like 4 in the morning). – TomTom Jun 16 '10 at 11:12

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