mark.cullen at dsl.pipex.com
Fri Apr 8 11:41:33 PDT 2005
Lowell Gilbert wrote:
> Mark Cullen <mark.cullen at dsl.pipex.com> writes:
>>Lowell Gilbert wrote:
>>>Mark Cullen <mark.cullen at dsl.pipex.com> writes:
>>>>Right, I have this weird annoying issue with my modem which I have
>>>>finally got around to looking in to. Basically, it's all good and
>>>>works fine (obviously, otherwise I wouldn't be here!), except when I
>>>>reboot the internet computer the IP will change, the connection
>>>>DOESN'T drop, but the IP does change. I have just now narrowed this
>>>>down to some sort of problem with dhcp I think.
>>>>The modem has a dhcpd server built in, which sends out the internet IP
>>>>address to the computers network card. It seems, whenever the dhcp
>>>>client, dhclient in this case, gets restarted it'll get the old ip
>>>>address (the first chunk of the quote below, before the <freeze>),
>>>>natd will update itself, but then the connection will just stall until
>>>>dhclient does the next DHCPREQUEST thing (47 seconds in this case?)
>>>>.. then the modem sends back a DHCPNAK and I get a different IP
>>>>address. Any ideas why this might be happening?
>>>Your "modem" is clearly the source of the problem, and it seems
>>>unlikely that anything on the FreeBSD side could help, aside from
>>>maybe forcing a lease free before starting dhclient on startup.
>>>I'd try looking at the configuration for that "modem" device, or
>>>possibly for a firmware upgrade for it.
>>Could you explain what's going on to me? I mean, in simplified terms,
>>what exactly is causing the modem to get a new IP address when
>>dhclient restarts? I have contacted them about the issue and they
>>seem to think it's an O/S problem (well, it's *obviously* not an issue
>>with their modem now, is it? :-P).
> Okay, now I'm confused. I thought your FreeBSD machine was the one
> being issued a new address, not the modem. [And that since the
> address was being issued *by* the modem, it was making the decision
> about which address to choose. I guess that means I was assuming your
> "modem" was doing NAT. Does the modem have an address at all?
Ooops, sorry. The FreeBSD machine does have the IP address assigned to
it's network card. I don't quite know how it works, but they seem to
call it 'Live IP technology'. I think maybe most people know it as 'PPP
The address is issued, to the FreeBSD network card, by the modem via
DHCP. The FreeBSD machine does the NAT and everything. As far as I am
aware the modem actually holds the IP, so it's kind of annoying that,
just because dhclient gets restarted, the modem decides that the IP
address has to change. Surely, since the modem's actually doing all the
work and holding the connection, it should be able to give me back my
old IP address?? Shouldn't it?
>>How would I go about forcing a 'lease free'? Delete dhclient.leases,
>>or some option somewhere that I missed?
> I'm pretty sure that dhclient(8) has an command-line option to do it.
Ok, I will have a look and give it a try!
>>As for configuration, there's no config for the DHCP server and
>>there's never been a firmware upgrade for it (this is the only issue I
>>have EVER had with it and I expect most users don't notice it).
> Since you've rebooted your computer anyway, why do you care? You've
> just lost all of your connections already.
Because I would like to try and keep the same IP as long as possible :P
I've been given admin on a game server that goes by IP address and
cannot afford my ISPs 'static IP' options. Furthermore, they stopped
with the 'sticky IP addresses' apparently :-(
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