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#61
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How does setting a static IP on a mobile device prevent linuxrouter from assigning that IP address?
On 2017-04-12, Pascal Hambourg wrote:
Le 12/04/2017 Ã* 14:14, Whiskers a écrit : Setting his phone to use a static IP while connected to his home network, would be a good idea if (when) he sets his router to use a static IP for that device. This does not make sense. A static address for a device is set on the device, not on the router. Addresses using dhcp, are set by the router. And a router can be set up to always give a certain MAC the same IP address always. It is also possible to set an IP on the device itself, but that you had better clear with the AP administrator, as the danger is may devices having the same IP, especially if many of th edevices are on dhcp. NOw with most routers as AP YOU are the administrator, so YOU had better make sure your device does not have the same IP as something else. As has been mentioned ad nausium here, there are many ways of doing so. As has been stated, most routers reserve a certain address space for dynamic IP requests. So you had better make sure that your static IP is not one of those. Most routers also are willing to assign a specific IP for a specific MAC if you register that MAC with the router. routers will also router stuff for a machine which simply says it is at a certain IP address (int he router's range) (ie the device simply assumes an IP). So lots of things are possible. |
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#62
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How does setting a static IP on a mobile device prevent linuxrouter from assigning that IP address?
On 2017-04-12, nospam wrote:
In article , Frank Slootweg wrote: he hasn't said *why* he wants this, and quite likely, there's an even easier solution. He *has* said why he wants/needs this - a fixed ip address on his phone while at home that's not a why. he has not stated the problem he needs to solve and has demonstrated that he knows very little about networking. I am so sorry. I know it is a terrible thing to have your memory go. He HAS said why. He wasnts to be able toaddress his phone so he can ftp to it, and transfer files to and from the phone using his Win computer. As such not having to figure out what the IP address of the phone is each time he does so is a convenience and he wants that convenience. his *guess* is that a static ip is the solution without realizing all the problems it will cause for both himself and others. Having the router always give his phone the same IP is not a problem. Having his phone assume an IP is also not a problem on his home network is also not a problem on his home network is also not a problem if he is careful to make sure he does not assign from the router's dynamic IP range and that nohting else has that IP. It can be a problem if he then takes his phone onto another network. -, but as usual you spout all kind of ******** without even knowing what the problem is. he never said what the problem is, so nobody, including you, has any idea. See above And yes, his want/need *is* a legitimate one. no it isn't. there is no valid reason why a *phone* needs a static ip address. |
#63
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How does setting a static IP on a mobile device prevent linuxrouter from assigning that IP address?
On 2017-04-12, nospam wrote:
In article , Mark Lloyd wrote: Since "Static DHCP" is a contradiction in terms, Static IP served by DHCP. Doesn't sound like a contradiction. just what do you think the 'd' in dhcp stands for? hint: dynamic. expanding it gives: static dynamic host configuration protocol, which is a contradiction. No. The router does not do symantic parsing. It serves IP addresses. You can, on most routers, tell it to serve a particular IP to a particular MAC. That Many people call "static". It is the same IP address always. It is also what most AP call static. Yes, DHCP is used, but he address is static. "static DHCP" could also apply to a DHCP server that supplies ONLY static IPs. I have used software like that before, although you probably will NOT find it on your router. a static ip by definition is not handed out by a dhcp server. it's configured on the device. Unfortunately definitions are not cooked up by each individual but come from common useage. |
#64
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How does setting a static IP on a mobile device prevent linux router from assigning that IP address?
On 12 Apr 2017 21:29:13 GMT, Frank Slootweg
wrote: Since "Static DHCP" is a contradiction in terms, is it so silly to say "Static IP" when the actual setting in some router is "Static DHCP IP"? No, of course it isn't, because it leaves out the silly contradiction in terms. That the static IP is probably managed by the same function which also assigns dynamic IPs is totally irrelevant. Sigh. I think we can all agreed that a (real) static IP LAN address is NOT delivered by the DHCP server in the router, while a dynamic IP LAN address is delivered by the DHCP server in the router. Any objections so far? Not hearing any, we have our first problem when the static IP address is configured to be in the middle of the DHCP IP address pool. For example, some routers assign almost the entire Class C IP address block to DHCP, usually 192.168.1.2 through 192.168.1.254. That makes it rather difficult for users to assign static IP's to their computahs, servers, print servers, etc, and not have the router try to assign the same address to some other machine. The obvious fix is to assign a smaller chunk of the Class C IP address block (such as .100 to .199) to the DHCP address pool in the router and not use these for static IP's, but what happens if the administrator or owner does do this and leaves everything at the default settings? It's now the routers job to figure out which IP addresses are being used on the LAN. It can do this by pinging a prospective IP address, sniffing traffic, digging though recent DHCP assignments (for dealing with machines that randomly connect and disconnect), or looking at the ARP table for addresses in use. There's an RFC for each of these. None of them are deemed "required", which give router manufactures a great opportunity to do leave them out, with predictable results. In theory, if one sets a static IP address for some (mobile) device on a network managed by a router, the router will be able to detect the presence of that device, it's MAC address, and what IP address it is using by one of the aforementioned methods. It will then not assign in use addresses via DHCP. However, I wouldn't count on it. Just keep the DHCP IP address pool, and the static assigned IP addresses separate and you won't have a duplicate IP address problem. Incidentally, a fun DHCP problem is drive-by DHCP, where a wireless client, laptop, or smartphone literally drives past an open (no WPA encryption password required) wireless router, which then assigns it an IP address. Comcast "gateways" do that so they can do their xfinitywifi thing. The problem is that unless the router is set to expire such DHCP assignments rather quickly, the ARP table will rapidly fill up causing the router to do "unexpected" things. ARP table overflow is one reason that some coffee shop routers need to be rebooted quite often. Of course, there's a security problem with sequentially assigning IP addresses via DHCP. Some evil hacker (like me) might be able to predict the assigned IP address of some device as it is turned on or wakes up. Then, the evil hacker can spoof that IP address on the network and impersonate the device. So, there's some RFC for randomizing the assignment of IP addresses by DHCP. Finally, if you're not asleep from the boring lecture by now, we have what I'll designate as "pre-assigned, pre-configured, or reserved static DHCP". There are other names for it, but the mechanisms are identical. It's considered static because it doesn't change. If you don't like the term "static", you might be able to substitute something that means "does not change". It's pre-assigned or reserved, because the DHCP server is configured to look at the clients MAC address, and check a list of IP and MAC address pairs, that match the clients MAC address. If they match, then the DHCP server assigns it a specific IP address. This is really handy if you want all your machines and devices configured for just DHCP, without having to configure IP addresses for the machine, netmask, default gateway, DNS servers, static routes, etc. Another cool feature is that a machine can be moved from the network with the pre-assigned static IP address, plugged into another networks with a completely different router, and still work without reconfiguration. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#65
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How does setting a static IP on a mobile device prevent linux router from assigning that IP address?
In article , William Unruh
wrote: he hasn't said *why* he wants this, and quite likely, there's an even easier solution. He *has* said why he wants/needs this - a fixed ip address on his phone while at home that's not a why. he has not stated the problem he needs to solve and has demonstrated that he knows very little about networking. I am so sorry. I know it is a terrible thing to have your memory go. He HAS said why. eventually he did, but not initially. He wasnts to be able toaddress his phone so he can ftp to it, and transfer files to and from the phone using his Win computer. As such not having to figure out what the IP address of the phone is each time he does so is a convenience and he wants that convenience. if he was interested in convenience, he wouldn't be asking about static ips. he'd be asking about dns so he doesn't need to remember any ips. his *guess* is that a static ip is the solution without realizing all the problems it will cause for both himself and others. Having the router always give his phone the same IP is not a problem. yep. it's very easy to do with almost any router (a few don't support reserved dhcp but not many). Having his phone assume an IP is also not a problem on his home network is also not a problem on his home network is also not a problem if he is careful to make sure he does not assign from the router's dynamic IP range and that nohting else has that IP. it's not a problem only if he takes the time to configure it correctly and guarantee there are no conflicts as well as always remembering to change it when leaving the house and changing it back when returning. that's a lot of ifs. otherwise, it's a problem. It can be a problem if he then takes his phone onto another network. it almost certainly *will* be a problem on another network, both for him as well as others using the network. |
#66
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How does setting a static IP on a mobile device prevent linux router from assigning that IP address?
In article , William Unruh
wrote: Since "Static DHCP" is a contradiction in terms, Static IP served by DHCP. Doesn't sound like a contradiction. just what do you think the 'd' in dhcp stands for? hint: dynamic. expanding it gives: static dynamic host configuration protocol, which is a contradiction. No. The router does not do symantic parsing. It serves IP addresses. nobody said the router did semantic parsing. *humans* do the parsing and the term 'static dynamic' is contradictory. the router doesn't know nor care what humans calls it. the router just moves the bits however it's configured. You can, on most routers, tell it to serve a particular IP to a particular MAC. That Many people call "static". It is the same IP address always. true It is also what most AP call static. not true. Yes, DHCP is used, but he address is static. true. "static DHCP" could also apply to a DHCP server that supplies ONLY static IPs. I have used software like that before, although you probably will NOT find it on your router. a static ip by definition is not handed out by a dhcp server. it's configured on the device. Unfortunately definitions are not cooked up by each individual but come from common useage. which is what i've been saying all along. |
#67
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How does setting a static IP on a mobile device prevent linuxrouter from assigning that IP address?
On 04/12/2017 05:31 PM, nospam wrote:
[snip] a static ip by definition is not handed out by a dhcp server. it's configured on the device. "Static is fixed, not changing. -- Mark Lloyd http://notstupid.us/ "The world is proof that God is a committee." [Bob Stokes] |
#68
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How does setting a static IP on a mobile device prevent linuxrouter from assigning that IP address?
On 04/12/2017 05:31 PM, nospam wrote:
[snip] It's a static (constant, doesn't change) IP. It's just the DHCP server, rather than the client device, that keeps it static. it's dynamically assigned. it's just that the dhcp server reserves the same one each time. Strange use of the word "dynamic", for something that DOESN'T change. Possibly theres confusion between a DYNAMIC process and a STATIC value. -- Mark Lloyd http://notstupid.us/ "The world is proof that God is a committee." [Bob Stokes] |
#69
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How does setting a static IP on a mobile device prevent linuxrouter from assigning that IP address?
On 12/04/2017 10:28 PM, Pascal Hambourg wrote:
Le 12/04/2017 à 14:14, Whiskers a écrit : Setting his phone to use a static IP while connected to his home network, would be a good idea if (when) he sets his router to use a static IP for that device. This does not make sense. A static address for a device is set on the device, not on the router. Could I suggest, by way of an example, that it is not a House that determines its address, it is the *location* of the house on a street that determines the house's address. So a device is just a device, and doesn't really need an address until it is connected to something else ... printer to computer, computer to router, router to server, etc., etc. Now, when we talk about Caravan or Winnebago, ..... that's something else!! ;-) Daniel |
#70
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How does setting a static IP on a mobile device prevent linuxrouter from assigning that IP address?
On 2017-04-12 14:39, nospam wrote:
In article , Whiskers wrote: Google "address reservation". You don't want a fixed IP address on a phone. Not true, he does. he might think he does, but he doesn't. Your opinion noted. it's not an opinion. he should *not* have a fixed ip address on his phone. that is only going to cause a world of problems, especially since he doesn't understand what he's doing. what he wants is a reserved address, which is done at the router. Setting his phone to use a static IP while connected to his home network, would be a good idea it's a horrible idea because he'd have to change it every time he leaves the house and back again when he returns. Not at all. -- Cheers, Carlos. |
#71
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How does setting a static IP on a mobile device prevent linuxrouter from assigning that IP address?
On 2017-04-12 20:55, Mark Lloyd wrote:
On 04/12/2017 09:57 AM, mike wrote: [snip] I referred to it as address reservation. It's functionally equivalent to static IP when used with the home router. It is. The difference is where you make the settings, and the fact that the device automatically becomes dynamic when on a different network. Notice that the way it is set currently it is static on his home only, dynamic elsewhere. There is no problem whatsoever, just a matter of choice. -- Cheers, Carlos. |
#72
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How does setting a static IP on a mobile device prevent linuxrouter from assigning that IP address?
On 2017-04-12 19:50, nospam wrote:
In article , Frank Slootweg wrote: he hasn't said *why* he wants this, and quite likely, there's an even easier solution. He *has* said why he wants/needs this - a fixed ip address on his phone while at home that's not a why. he has not stated the problem he needs to solve and has demonstrated that he knows very little about networking. Yes, he did say it. And it is a legitimate reason. -- Cheers, Carlos. |
#73
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How does setting a static IP on a mobile device prevent linuxrouter from assigning that IP address?
On 2017-04-13 02:08, William Unruh wrote:
Having the router always give his phone the same IP is not a problem. Having his phone assume an IP is also not a problem on his home network is also not a problem on his home network is also not a problem if he is careful to make sure he does not assign from the router's dynamic IP range and that nohting else has that IP. It can be a problem if he then takes his phone onto another network. Not even then, because the configuration is not generic. It applies only to a single SSID. He connects to another AP, and it gets DHCP again. -- Cheers, Carlos. |
#74
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How does setting a static IP on a mobile device prevent linuxrouter from assigning that IP address?
On 2017-04-13 06:32, nospam wrote:
In article , William Unruh wrote: he has not stated the problem he needs to solve and has demonstrated that he knows very little about networking. I am so sorry. I know it is a terrible thing to have your memory go. He HAS said why. eventually he did, but not initially. He did, on the first post: On any mobile device (iOS, Android, whatever), you can set up an FTP server (eg ES File Explorer on Android) with a static IP address so that Windows "My Network Places" has a permanent "shortcut" to the entire mobile device file system (eg ftp://192.158.1.15:3721). This is very useful, and I've been using it for a couple of weeks ever since it was discussed here - because it effectively mounts the mobile device as a network drive on Windows without adding any new software on either Android or Windows. Notice the mention to "since it was discussed here". It is a reference to another thread. He wasnts to be able toaddress his phone so he can ftp to it, and transfer files to and from the phone using his Win computer. As such not having to figure out what the IP address of the phone is each time he does so is a convenience and he wants that convenience. if he was interested in convenience, he wouldn't be asking about static ips. he'd be asking about dns so he doesn't need to remember any ips. You are assuming he has a router with that capability. I have seen none. -- Cheers, Carlos. |
#75
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How does setting a static IP on a mobile device prevent linuxrouter from assigning that IP address?
On 2017-04-12 22:21, Stephen wrote:
On Wed, 12 Apr 2017 02:54:24 +0200, "Carlos E.R." wrote: c) You happen to have a router that before assigning an IP, first pings that IP to see if it responds, then automatically removes that IP from the pool of addresses it can give. FWIW most home routers seem pretty brain dead for the optional subtleties in the DHCP server standards - several types i have used will merrily hand out the same IP address that is in use by a device after a reboot. Yes, indeed. I have not seen any home router doing that check. They may exist, though. -- Cheers, Carlos. |
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