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From: Rikishi42 on 5 Jul 2010 17:04 >> What server gives you the IP? Your own broadlband/ router ? >> If so, it might have the option to allways give the same IP to a machine >> with a given MAC. > > If it's his own router, it will most likely have a block of addresses > to give out to other devices. Picking an unused one outside that block > should work. But then he'd still have to fix his IP manually. Where possible, have his own DHCP fixing it, is easyer and more flexible. His machine can stay in DHCP and be used in another network if needed. >> If it's a server you can't control, then fix it in Yast/Network >> Devices/Network settings. > > That depends on whether the IP address is a private address, or one > assigned by his ISP. If it's a private one, then he can fix it. If it's > ISP assigned, no he can't. You're right of course, I was thinking about a router without DHCP function. Can't really picture a home connection without a private network anymore, it's been too long. -- When in doubt, use brute force. -- Ken Thompson
From: David Bolt on 5 Jul 2010 18:05 On Monday 05 Jul 2010 19:33, while playing with a tin of spray paint, Maurice Batey painted this mural: > On Mon, 05 Jul 2010 19:22:41 +0100, David Bolt wrote: > >> If it's his own router, it will most likely have a block of addresses >> to give out to other devices. Picking an unused one outside that block >> should work. > > If there are several terminals on a LAN, there is a need to ensure > each maintains the same IP address regardless of the order in which > they are booted, otherwise the router is likely to allocate the first > of a series to the first to be booted, which makes inter-LAN > addressing difficult. That would depend on the DHCP server and whether it can retain the leases it hands out. For things like routers, this would be an issue since while they remember settings and, as you mention below, MAC to IP addressing, they don't remember ordinary IP assignments. If you have your own DHCP server, you can set up "static" assignments so that the machine asks for an IP and it's always given the one assigned to the MAC address. Machines that don't have a known MAC address are then assigned an available IP. Having said that, in theory a machine should ask for the last assigned IP address from the DHCP server which, as long as it's not been assigned in the meantime, should assign it to the requesting machine. If the pool of available IP addresses is too small for the number of machines, but enough are free to cater for the machines in use, some IP addresses would be recycled and so unavailable for the requesting machine. > (I fell into that trap, and escaped via the router (Netgear > D834G) facility to allocate IP address according to the MAC > address of a teminal's NIC (Network Interface Card), thus ensuring > each terminal always has the same IP address, regardless of the order > in which they were booted.) For a normal home network, one consisting of maybe five to ten devices requesting IP addresses, the available IPs should be enough. If not, it's possible to expand the range. For larger networks, it may be a better idea to set up your own DHCP server, where you can control things better than you can with a small home router[0]. This is exactly what I've been doing for several years. With the addition of a DNS server, so I don't need to remember to update the hosts file on any new machines added to my network, and a TFTP server so I can do network booting and installations. This makes it easier to add new machines, virtual or otherwise. [0] I now use a DG834G, with either a DG834GT or Speedtouch 585 router as backup and disabled the DHCP on them all. Don't fancy causing network chaos by having two DHCP servers running on the same network at the same time. Regards, David Bolt -- Team Acorn: www.distributed.net openSUSE 11.0 32b | | | openSUSE 11.3RC1 32b | openSUSE 11.1 64b | openSUSE 11.2 64b | TOS 4.02 | openSUSE 11.1 PPC | RISC OS 4.02 | RISC OS 3.11
From: David Bolt on 5 Jul 2010 18:44 On Monday 05 Jul 2010 22:04, while playing with a tin of spray paint, Rikishi42 painted this mural: > > >>> What server gives you the IP? Your own broadlband/ router ? >>> If so, it might have the option to allways give the same IP to a machine >>> with a given MAC. >> >> If it's his own router, it will most likely have a block of addresses >> to give out to other devices. Picking an unused one outside that block >> should work. > > But then he'd still have to fix his IP manually. Where possible, have his > own DHCP fixing it, is easyer and more flexible. His machine can stay in > DHCP and be used in another network if needed. True. My thought here was that he should[0] be getting the same IP address each time he reboots, unless there's a number of machines on his network going on and off, and the number that is on at any one time just about fills the block of addresses used for IP address allocation. That is, of course, unless he powers down his router as well as his machines, in which case setting them up to be assigned "static" IP addresses would be "A Good Thing"(tm). >>> If it's a server you can't control, then fix it in Yast/Network >>> Devices/Network settings. >> >> That depends on whether the IP address is a private address, or one >> assigned by his ISP. If it's a private one, then he can fix it. If it's >> ISP assigned, no he can't. > > You're right of course, I was thinking about a router without DHCP function. That was another thought. If he's using a cable modem, that may just pass the IP address through, basically the same as a router in bridged mode. > Can't really picture a home connection without a private network anymore, > it's been too long. It's been a while since one of my machines had a non-private IP address. At that time I was using PPP and a dial-up, initially analog and then ISDN, and the machine routed for the private network behind it. [0] From watching requests made to the ISC DHCP Server as used by openSUSE, if the NIC was already assigned an IP address, it requests that address again. In my case, I've only ever seen one refusal, which because the machine had been used on another network and acquired a different IP address to one it would have been allowed, and in that case a request was then made for a new address and one offered. Regards, David Bolt -- Team Acorn: www.distributed.net openSUSE 11.0 32b | | | openSUSE 11.3RC1 32b | openSUSE 11.1 64b | openSUSE 11.2 64b | TOS 4.02 | openSUSE 11.1 PPC | RISC OS 4.02 | RISC OS 3.11
From: Maurice Batey on 6 Jul 2010 07:22 On Mon, 05 Jul 2010 23:05:33 +0100, David Bolt wrote: > If you have > your own DHCP server, you can set up "static" assignments so that the > machine asks for an IP and it's always given the one assigned to the > MAC address. "the machine" implies 'every machine on the LAN', has to do that. I'm happy that - once the router's IP-allocation table has been set - none of the machines on the LAN has to do any IP allocating. -- /\/\aurice (Replace "nomail.afraid" by "bcs" to reply by email)
From: David Bolt on 6 Jul 2010 11:00
On Tuesday 06 Jul 2010 00:04, while playing with a tin of spray paint, houghi painted this mural: > David Bolt wrote: >> Having said that, in theory a machine should ask for the last assigned >> IP address from the DHCP server which, as long as it's not been >> assigned in the meantime, should assign it to the requesting machine. > > Yeah and in theory I should be earning a gazillion bucks a month. mean > while in real life it does not seem to happen. ;-) If theory, theory and practise should be the same. In practise, they rarely are :( >> For a normal home network, one consisting of maybe five to ten devices >> requesting IP addresses, the available IPs should be enough. > > The standard I have now configured is 192.168.1.2 192.168.1.254 > One time 5 would not be called "standard" but now with the many > (wireless) devices it is not that much of a shock anymore. Which is one reason I said that the pre-configured range may not be enough, depending on just what range is given. My DG834G has 2-254, which would need altering if I ever used it as a DHCP server, as it is assigned .254. No idea if this is the default range, or if I altered it at some point. An older router I had had a much smaller range, and I don't know what range the 585 has without digging it out and either swapping out the 834 or connecting separate machine to it since it would act as my gateway and so has the same IP address as the 834. > I only have > two devices, but I know people who have the following: > 1 x Standard main PC > 2 x portable (one for him, one for her. Both from work) > 1 X xbox > 2 x cellphone (iPhone and normal one) > > That is 6 already and nothing special. Add some kids to the household > and it will go up. Especially if they have smart phones of some sort, certain portable consoles, their own netbook , etc. >> If not, >> it's possible to expand the range. For larger networks, it may be a >> better idea to set up your own DHCP server, where you can control >> things better than you can with a small home router[0]. >> >> This is exactly what I've been doing for several years. With the >> addition of a DNS server, so I don't need to remember to update the >> hosts file on any new machines added to my network, and a TFTP server >> so I can do network booting and installations. This makes it easier to >> add new machines, virtual or otherwise. > > In a previous modem/router/hub/firewall I was able to get 4 fixed IPs. > Now I can have as many as I desire. I just go to the apropriate settings > and add them. I can have only allowed up to a 128 dynamically allocated IPs, split up into a couple of blocks containing 80 and 48 IPs. The rest of the /24 contains unused ranges, static IPs and some more that are "fixed" inside the DHCP config. So far, I've some way to go before I'd need to add any new ranges as I've not yet used up the IPs in the 48 address pool, and some of the leases that have been remembered are now at least three years old and are mostly for virtual machines that were created, used for a quick test end then deleted. Regards, David Bolt -- Team Acorn: www.distributed.net openSUSE 11.0 32b | | | openSUSE 11.3RC1 32b | openSUSE 11.1 64b | openSUSE 11.2 64b | TOS 4.02 | openSUSE 11.1 PPC | RISC OS 4.02 | RISC OS 3.11 |