ChasN
@co.uk
| [ADSL] Newbie router IP address question
This is dumb, but I'd like to understand.
I've just taken up ADSL in the UK, using Demon as my ISP. Demon have assigned me a static IP address. I have just bought a combined router/modem/switch/firewall from Netgear.
My Internet IP address:
Part of the router configuration lets me choose, for 'Internet IP address' whether to 'Get Dynamically From ISP' or 'Use Static IP Address' - if the latter, then I can enter an IP address.
DNS address:
Demon have given me primary and secondary DNS server IP addresses. Like for my Internet IP address, the router configuration lets me either select 'Get them automatically' or lets me input them.
I called Demon tech support, who said I can leave both these (Internet IP AND both DNS addresses) as automatic.
Now, for the DNS addresses, I can see how this might be sensible - even though they've told me some addresses, I guess that normally my connection would automatically find the DNS server - and after all, for dial-up it was also always possible, in Windows, to manually set the DNS addresses, but never really necessary for me (I did once when there were some connection problems, but it was a red herring, the problems were elsewhere).
But for the Internet IP address, I really don't understand. If Demon have allocated me a static IP, and I don't tell the router that address, how does it ever happen that traffic would get to my router? Does the ISP dynamically tell it the static address assigned to me when I log on, or something? |
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Edd1e
join:2004-02-24
uk | The Isp would allocate you ip to you when the modem logs on to the server. it's part of the logging in procedure.
Eddie |
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Imogen8
join:2001-11-04
UK
| reply to ChasN
Its works more or less the same as dialup on ADSL... except when you dial (or the router does) it gets the same IP address everytime (static)...
Just do as tech support advised... afterall thats whats they are there for  |
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ChasN
@uk.t
| OK thanks. I do listen to tech support, really.
Only this Demon one wasn't really very confident or convincing, and kept trying to tell me not to worry about the DHCP assignment of IP addresses within my own little home network - so I didn't think he understood.
Plus the router manual is pretty clear that it wants me to enter a static IP address in the appropriate configuration field. Their tech supp is now in India - it took more than 10 minutes (really) for him to get my name and address, and when we got totally stuck on the 15 digit/letter serial number I gave up in disgust - maybe he'd have known the answer if he'd understood the question, but he'd never have understood the question.
So, I understand that my router will fetch an address from my ISP when I connect, and because my ISP offers me a static IP, that will always be the same. |
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StrangerNoDanger
| »Cisco Forum FAQ »Configure PIX/ASA as both Internet Firewall and VPN Concentrator
Have a look at the first question and answer in the faq posted above.
There is no real difference between the two and ISPs automatically configure the DHCP server to allocate that IP to you whether you configured it statically or not on your router as it makes management easier. |
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Traduk
join:2000-10-25
England
| reply to ChasN
ChasN,
>>So, I understand that my router will fetch an address from my ISP when I connect, and because my ISP offers me a static IP, that will always be the same.
My ADSL is with Zen and I have a fixed IP. It appears to be standard to select DHCP type collection of the ISP's IP even though it is not dynamic but fixed. In theory and in practice it doesn't matter either way because you will always get the IP you have been allocated.
I changed mine to the fixed input as opposed to dynamic because I was troubleshooting on a distant connection and did not want the router to request an ISP address. For me it works either way. My router has a timer for dynamic address lease renewals and even though it's set for fixed it still goes out every 3 days (setting in options) and renews even though it's pointless.
Traduk |
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