A few days ago my internet provider automatically changed my Wi-fi network name.

I was very annoyed because I add to reconfigure all my devices, and I had no choice to refuse this update.

As they are able to alter my router configuration. I wonder to what extent they can control things in my local network.

  • Can they access my computer from the outside ?
  • Should I consider buying a custom router to have more control over my network?
  • Did any other settings change? Maybe they pushed out a firmware update and your router went back to default settings. – Brian Duke Dec 26 '15 at 23:52
  • I had changed the name of the 5Ghz Wi-Fi and it did not change. Only the 2.4 Ghz Wi-Fi name changed – Octoplus Dec 26 '15 at 23:55
  • How can you conclude that your ISP did it? It could have been a bug or something. Also, if you don't trust someone, you shouldn't be paying them to provide you with internet. – multithr3at3d Dec 27 '15 at 0:10
  • They sent me text messages on my phone to tell me they would do it. I just did not have the choice to say yes or no. – Octoplus Dec 27 '15 at 0:11
  • If you distrust your ISP you might want to use a VPN. In that case, of course, you'd have to trust a a VPN provider way less regulated than an ISP. – Zsolt Szilagy Dec 7 '16 at 22:11

I would be very surprised if your ISP can change the settings of your router. I suspect that they changed the settings of their router that you rent. If you are unhappy with this, use your own router after changing all default passwords and enabling other appropriate security settings.

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  • Yes indeed it is "their" router but I don't see how they can alter its configuration without some super user access as I changed its password. – Octoplus Dec 27 '15 at 0:12
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    The manufacturer or ISP (via a custom rom) has included a backdoor for the ISP to use. It could be a hidden account or other mechanism. – Neil Smithline Dec 27 '15 at 0:15
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    It's quite common for the ISP to have a "backdoor" to update the firmware on routers that they supply (regardless of who actually owns the router). That way they can push out updates for functionality or security without trying to explain to every single customer what they need to do to perform an upgrade. – Simon B Jan 26 '16 at 10:50

If you have the choice about the matter for phone company Internet access, provide your own DSL modem, for cable internet access, provide your own cable modem. When they apply firmware upgrades, it will only affect this piece of equipment

Then run a separate Ethernet Firewall/Router with builtin Wireless Access Point so you have reasonable control over your own home security. You can then keep this part of the hardware package upgraded to the latest firmware from the manufacturer and retain control over your firewall administration access and assigned SSIDs.

The reason for these changes you mentioned is that ISP owned DSL and Cable Modems require security and firmware stability upgrades just like everything else on the planet.

The ISP has stock setups that get pushed, and just like doing firmware upgrades to your own equipment, the current configuration settings may not survive the firmware upgrade so they have defaults that get reapplied so the darn thing at least works. Doesn't bode well if it resets admin access credentials system-wide to something that's known, at least they notify you so you might be able to change them to something more secure.

BTW, was this Canadian DSL equipment (HomeHub 1000/2000)? There were some egregious issues reported earlier this month with a hard-wired password on them and the issue you mentioned is actually a very desirable side issue to the firmware upgrade they need to protect you if they've finally got around to it. Qwest DSL modems from a certain manufacturer might also have the same issue as well.

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  • No this was the french DSL company SFR. – Octoplus Dec 28 '15 at 15:05
  • This answer pretty much covers it, so +1, just to clarify, if changing ISP is not possible and you can't change the router for your own, then garden wall their router with your own (ISP)<->(ISP Router)<->(your Router) – Paul Grove Jan 26 '16 at 11:57

Typically, ISPs have access to change and update their hardware. If you're renting your hardware from them, then they will have credentials to update and reset it as required.

What likely happened was that they pushed a firmware update out which simply reset your hardware to factory defaults. It's a bad policy, but not uncommon, and not something that you can stop without violating your contract.

What you can do is to either replace their modem/route with one you buy and control, or add it into the chain (so that the network and wireless are served by your device, and your device is the only one that connects to your ISPs modem), but do understand that they didn't change your device, they changed theirs.

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I would recommend changing your ISP immediately. This is a non-standard practice and i've never heard of anything like this before.

Also, to answer your original question "Can I prevent my ISP from accessing my network if I change my router config?"

If you change the login/password for your router, this should do the trick.
Also, disable all ports except 80.
Your ISP may have run a script across all customers, so your router's login/password is either the default one, or one that was created by your ISP.

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    Unfortunately, this is semi-standard for built in router / modem combo rentals from the big cable providers. Such as: techdirt.com/articles/20141208/13222529362/… – user84662 Dec 27 '15 at 1:45
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    That's insane! Who would think of such a crazy idea? – 16b7195abb140a3929bbc322d1c6f1 Dec 27 '15 at 1:48
  • That's kind of what bothered me, I did change the login/password because it was "admin" and "password" ... But they have been able to alter my router config... – Octoplus Dec 28 '15 at 15:06
  • I actually think that this is a very good idea, not insane at all. Most users will never update their router firmware, so vulnerabilities will never be fixed. You can always use your own router if you want to avoid this. – Pablo Jan 26 '16 at 11:03

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