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Am Fri, 31 Oct 2014 07:09:08 -0400 |
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schrieb Rich Freeman <rich0@g.o>: |
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|
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> On Fri, Oct 31, 2014 at 6:47 AM, Marc Joliet <marcec@×××.de> wrote: |
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> > Am Fri, 31 Oct 2014 07:52:54 +0100 |
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> > schrieb "J. Roeleveld" <joost@××××××××.org>: |
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> >> On Tuesday, October 28, 2014 07:31:56 PM Marc Joliet wrote: |
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> >> > |
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> >> > - I don't know whether we have an IP block or not; I suspect not. At the |
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> >> > very least, we didn't make special arrangements to try and get one. |
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> >> |
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> >> Then assume not. Most, if not all, ISPs charge extra for this. (If they even |
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> >> offer it) |
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> > |
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> > That's what I thought :) . |
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> > |
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> |
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> Generally speaking you can't just attach a modem to your LAN and have |
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> it act as a DHCP server. Your ISP probably will assign you dynamic |
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> IPs, but they will not as a matter of policy assign you more than one |
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> unless you pay for them. IPv4 address space is in short supply these |
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> days. |
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> |
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> I'm using FIOS and in my case the "modem" is in a box in the basement |
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> and the ISP provides a router with the service. Whatever you plug |
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> into the "modem" will obtain a DHCP lease for one routable IP. If you |
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> do plug more than one device into the "modem" then the first device to |
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> get the IP is the only one that will get an IP - the modem won't hand |
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> out another unless it gets a DHCPRelease from the MAC that was issued |
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> the original lease or until that lease expires, or until you call up |
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> the ISP on the phone and get them to release it manually. |
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> |
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> Another design would be to issue a new IP anytime a device asks for |
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> one, but to silently cancel the lease of the last IP that was issued |
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> and drop packets using it. For a single device being plugged in that |
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> won't have any impact, and if for some reason you buy a new router and |
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> plug it in you don't have to worry about your old router still having |
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> a lease. This is less standards-compliant, but perhaps more |
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> clueless-friendly. |
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> |
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> In general, though, you really shouldn't be plugging your ISP's modem |
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> into anything but a router for general use. In fact, I have the |
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> router provided by my ISP configured as a bridge and running into |
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> another router (FIOS uses MoCA over coax in the standard install and |
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> I'm too lazy to run CatV and beg Verizon to reconfigure the modem to |
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> use the RJ45 connection instead). Note that if you use an |
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> ISP-provided router there is a good chance that they can essentially |
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> VPN into your LAN. The last time I called up Verizon over a cablecard |
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> issue they helpfully turned on DHCP on my router so that it started |
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> competing with my DHCP server, and then I was wondering why PXE was |
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> randomly failing. Now all they can do is disable bridge mode, which |
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> will break my external connection and be a fairly obvious point to |
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> troubleshoot. |
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|
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Right, thanks for the explanation :) . |
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|
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Thankfully, our ISP only gave us the modem (though they also offer modems with |
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WLAN for 5€ a monthg :-/ ). The router we bought off eBay ourselves :) . |
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|
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-- |
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Marc Joliet |
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-- |
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"People who think they know everything really annoy those of us who know we |
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don't" - Bjarne Stroustrup |