How does setting a static IP on a mobile device prevent linux router from assigning that IP address?

If you're in the market for one, a Ubiquiti EdgeRouter ER-X is under 70 USD, and can do this. By default, it doesn't, but it can be enabled pretty easily.

Reply to
Dan Purgert
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Yeah, seems AT&T re-uses the default SSIDs across various regions (e.g. US East / US Central / etc.). Though, can't really blame them for doing it, the chances that two customers will cross regions AND know people who happen to have the same default SSID are obviously small enough that it's not a worry.

Reply to
Dan Purgert

The DHCP server should have a lease time; a day, a week. What is the result of an ipconfig /all? Can you post that here? It would be useful if we could see that.

And what is the router/modem (the device with DHCP)? You could assign a DHCP reservation in it, probably. (Most newer router/modems support reservations.

(Microsoft do it beautifully in their server DHCP server software - you just right-click on any IP in it's list of assignments and 'reserve it' - job done, it's now in the Reservations list - no looking up fucken MAC numbers :) Don't do Linux DHCP servers, but I imagine it's a lovely command line thing :) )

Reply to
Dave Doe

Thanks, but I can not replace the ISP provided router. The configuration is complex, not documented, and they change it remotely now and then. It also handles the phone (via hidden VoIp) and the fibre TV. Too risky.

If I wanted, I would disable the dhcp server on the router and handle it myself on my server instead with a dnsmasq daemon. Not worth the hassle, though. Instead I use fixed IPs and defined DNS entries in my bind server.

Reply to
Carlos E.R.

Well, not so small a chance, it happened to you :-P

If they have such a large customer list, they should use longer SSIDs. I suppose it is a prefix then a decimal or hex number. They just need more digits. :-)

How many digits do they use, perhaps 4? Because 4 is what I see here. That's only 10000 customers, they surely have many millions. They are bound to collide.

Reply to
Carlos E.R.

Some routers have it point and clik, yes. And you know that most routers run a Linux variant ;-)

Reply to
Carlos E.R.

In , Dan Purgert suggested:

Yes. We use Microtik routers and Ubiquti equipment almost exclusively.

We set up the entire neighborhood and we maintain the equipment through all those storms and power outages we had this year.

We buy them in bulk, and put them in people's homes who need them (most often the Apple-based households need more handholding, for example).

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I don't use them because I have plenty of spare radios lying about, but these Unifi access points are super easy to set up so they're good for others, I agree.

Plus, they're a lot prettier than this Bullet M2 HP with 14dBi planar antenna AP lying on the floor in a spare room.

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I certainly understand that, which is why you saw those 18-inch dishes in the previous photos, where I used them to replace lesser-gain setups such as this one with a microtik board in it that is on the floor next to me.

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I get my Internet from an access point about 4 miles away, for example, so, I'm familiar with the 12 decibel SNR headroom that is generally useful to have for a decent connection to begin.

I had to switch from 2.4GHz to 5GHz, for example, just to lower the noise level.

You know this, but it's interesting to note for those here who don't buy the kinds of radios pictured here that a typical SOHO router has utterly puny EIRP compared to these radios (which easily operate up to the legal limit).

What's the EIRP of a typical home router (with a typical omni antenna)? Probably something like 18 decibels EIRP, right? (Jeff Liebermann has tested this thoroughly, by the way, so I'll defer to others who have run the test if those numbers are off - but my point is that, for the same price, we can get far more "power" than what a puny home router provides.

The rocketdish alone that you see pictured below gives you 30 decibels of (directional) gain!

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I can tell you know this, but my main point in this part of the discussion is to just say that, for about the same price, a router is a puny signal emitter compared to these (highly directional) setups.

However, since these setups are highly directional, you may need more of them (which is why the unify would be a good idea - if I didn't already have plenty of radios lying around).

As I learned more about WISP, I kept buying stronger radios with narrower beamwidths (more directional) antennas! :)

For example, here are some older radios lying around that have a wider beam width, but still, your point is well understood that these radios were never intended to be access points inside a home.

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They just happen to be available - so I used them - and - while they're very powerful - they're highly directional.

They're currently set up as "access points" in "bridge mode" as shown for the Rocket M5 below: ACCESS point:

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BRIDGE mode:
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The point is that I wouldn't use them as access points except that I have a dozen of these things lying around the house, so, they're free, and powerful, if directional.

I'm ok with that "napkin math" of a kilometer, when you compare that the typical home SOHO router, which costs about the same as any one of these radios do, gets you no more than about 100 meters, maximum, right?

I should summarize that I agree with you - but I happen to have a lot of powerful (directional) radios lying around - but most people would do well with the Unify access points instead - which is what you suggested.

Reply to
Tomos Davies

In , Dave Doe suggested:

The lease looks like it's a 24-hour lease from this output. Do you concur?

Here is a snippet of the ipconfig /all on Windows:

Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Broadcom 440x 10/100 Integrated Controller Physical Address. . . . . . . . . : 00-14-22-F3-AA-D1 Dhcp Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes IP Address. . . . . . . . . . . . : 192.168.1.235 Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : 192.168.1.1 DHCP Server . . . . . . . . . . . : 192.168.1.1 DNS Servers . . . . . . . . . . . : 192.168.1.1 Lease Obtained. . . . . . . . . . : Thursday, April 13, 2017 2:12:54 AM Lease Expires . . . . . . . . . . : Friday, April 14, 2017 2:12:44 AM

Based on the advice from this thread, I will probably set up the router to hand out addresses outside the range of what the phones are set up as.

It has been working so well without that, that I haven't had the need to do that yet.

Linux is pretty good nowadays with setup. I just set up a printer, and it went surprisingly easily (much much much easier than it was to set up that same printer on Windows 10 since Windows 10 doesn't seem to natively support my older HP Laserjet 2100 so I had to run a temporary Windows 10 update (which gets blown away the moment you leave the setup screen!) so it took me a few tries to get it into my head that Windows 10 makes it absolutely miserable if you don't know the exact secret sequence to update an older printer driver).

By way of contrast, on Ubuntu, the printer was working before I even knew it (much like this Android static IP setup was).

Sometimes Android and Linux are just too easy!

Reply to
Tomos Davies

In , Dan Purgert suggested:

Since the WPA2/PSK salt is the SSID I pretty much try to make my SSID's unique (along with as unique a passwd as I can come up with) in order to stay out of the many rainbow tables published on the net.

Given that, the likelihood of running into another SSID of the same name is probably pretty low.

:)

Reply to
Tomos Davies

In , Carlos E.R. suggested:

I agree with you.

All I did was a *single* AP setup on Android. No more than that - and it has been working for weeks.

From this discussion, I realize I have been "lucky", probably because of the lease period for the IP address assignment hasn't been exceeded.

The point of asking the question in the first place was because I was surprised it worked so well - because the router was never modified - and the excellent answers show that I was just lucky, as it might not work so well forever.

Reply to
Tomos Davies

I said "a lot can", which implies that some can't. If you can flash it, be sure to use a WIRED connection.

Yes.

BTW, DD-WRT had a form to specify this (it's called "static leases"). although I prefer to use the DNSMasq option, like:

dhcp-host=84:F2:77:3C:EE:E7,192.168.1.19,Gary

which includes the DNS name.

Reply to
Mark Lloyd

In , Carlos E.R. suggested:

I just checked one of my radios which allows only 32 characters in the SSID, where most of you probably have _nomap and _optout added for privacy reasons; so that means you only get about 19 unique characters that you have any control over.

Reply to
Tomos Davies
[snip]

You can always add your own router after that ISP provided one. If possible, have it forward all ports to your router. You may have to change an IP somewhere.

Some people say you shouldn't have more than one router. It's no problem when you set them up correctly. I sometimes use two (backup cellular hotspot, router with no ethernet port). I have the hotspot set to use a LAN subnet of 192.168.3.0/24, and my main router has a LAN subnet of

192.168.1.0/24. [snip]
Reply to
Mark Lloyd

I know how to do that, but for what purpose? There is nothing I would gain from it. Have a matching DNS and DHCP server? I do not need it.

It would add complications that I do not need, starting with more cables, more expense, more things to admin. Specially when the ISP router is handling at least two VPN of its own, not documented. Those would need to be handled by the secondary router as well in manners such that the TV and the phone keep working.

No, thanks.

Reply to
Carlos E.R.

I'm not sure what you mean by "C". Setting all the various AP's (access points) to the same IP address does absolutely nothing to the function of the AP. That's because all wi-fi wireless is done at Layer 2 (MAC address layer) and does not involve Layer 3 (IP address layer) in any way except to configure the AP using the built in web server. Setting all the various AP's to the same IP address is a guaranteed IP address conflict. You will not be able to access any of them until you assign each AP its own unique (static) IP address. Please note that most AP's do not have a DHCP *CLIENT* on the LAN side, and therefore cannot obtain a DHCP assigned IP address from your router.

Reply to
Jeff Liebermann

No worse than "military intelligence" -- oxymoron, maybe :-) .

Reply to
tlvp

I suspect he means configuring in his Android devices all the configs for his several AP of his home to have the same address. He does not mean changing the configuration of the AP themselves.

Then, again, it makes more sense to assign a fixed IP at the DHCP configuration of his router, which is one single configuration point for the entire house complex.

Reply to
Carlos E.R.

It's a lovely config file, thankyouverymuch :P

Reply to
Dan Purgert

Yeah, once over the course of $family and $friend each being AT&T customers for decades (and having several router upgrades in between).

The default SSID was something like 2WIRE_1a2b3c4d5e6f (the hex at the tail end changes -- definitely not the device MAC addresses, but some psuedo-random number)

Reply to
Dan Purgert

According to the documentation provided to the FCC, the Netgear Nighthawk R700 is ~27 dBm on 5 Ghz and ~29 dBm on 2.4.

And yet, you're still limited to 36 dBm EIRP (at least on 2.4 GHz) if using the AP in a Point to Multi-point configuration (such as for client device wifi access). PTP shots (one AP / one STA), the EIRP limit is higher though -- but if you ever connect a second STA to that AP ... :/

In an otherwise dead silent RF environment (same as previously), about

300 yards. Depends a bit on the specifics of the antenna in the router.

The point I was trying to make though was more about your implication that you can make *wifi* connections over a distance of *miles*. It's overly broad statements like that that end up with the first guy in some BFE thorp to finally get a 300-baud modem thinking he can share wifi to the entire community with a single rocket and AMO-2G-10.

And really, once you get somewhere that's not pretty much entirely dead RF wise; the distances are going to drop fairly quickly -- simply because of channel re-use and general noise on the spectrum. That 100 meters you mentioned is a good rule of thumb distance for most any community.

Reply to
Dan Purgert

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