When I was changing my router my ISP technician told me that he has remote access to all routers provided by ISP. Was that true? If that is a fact it scares me...
Go home. Plug a new router into the ISP router, or if you're courageous, replace the ISP router with your own router. Set the admin password to a 32 character "Horse Battery Staple Kumquat" value.
Now ask whether the ISP has access to all routers connected to their network.
The admin told you what it is useful (to him) for you to believe.
In a typical modern setup, the cable modem and router are the same device. It is both an endpoint on the consumer's network as well as the telecom's. As such, they have base level access to administer the device, however what they are allowed to do with it is generally governed by your terms of service. Even when the router is separate, if it is supported by the ISP, then they need access to it to be able to provide support.
This is why I never use the router provided by the ISP. If you want to be secure, you should always use your own hardware that you own as an additional layer of defense. I have my ISP's cable modem/router set in to bridge mode and it relays the connection to my personal router which treats it as a WAN device. This gives me complete control of my interior network, but it also means I'm on my own whenever there are problems with my connection and the first thing they make me do is plug in to the cable modem directly to eliminate my network as a possible problem.
ISPs have complete access to router provided by them. actually they us PORT 7547 which is TR-069 Protocol (CWMP customer-premises WAN management protocol). and you can not even disable it. because its hidden in GUI mode, and obviously ISPs don't provide Manageable Routers (CLI) based.
solution is just replace router with your own, by asking complete Router configurations from your ISP.
I highly doubt it, yes there may be limited access to the router itself most likely for diagnostics purposes. But having access through the router itself into your network is unlikely as there are numerous laws which would come into play e.g. in the UK we have the computer misuse act making it illegal to access your network directly without your consent. If you are worried you can do simple things to help put your mind at ease,
change the administrator password on the router
change the access password to your router
keep anti-virus software up to date (some may have anti-intrusion algorithms as well)
The chances are what he meant was that he (the ISP) will have a degree of access to routers which would allow them to carry out diagnosis in the event of a problem. Without reverse engineering the router though there is no way to be 100% sure but chances are he was making it up a bit. If all else fails i'm sure Edward Snowden will let us know soon
It's probably true, this is to speed technical support. ISPs have wasted huge amounts of time trying to walk customers through menus, so they have cut out the middleman. I'm guessing it scares you because:
- OMG, they can see everything that I do! Truth is, they already can, they're your ISP. Everything you do on the internet is an open book to them whether they control your router or not. OK, if they have control of your router they can sniff traffic between systems in your home network, chances are that's not a real concern
- OMG, they can control my network! So what? There's nothing that they could do on your router that they couldn't do from their routers
If having control of your router is important to you then talk to your ISP. Many ISPs now have it in the T&Cs that you use their provided router in order to get tech support, if you put your own on there it will probably still work but you'd be on your own if something goes wrong. You also may be able to pay a bit more monthly in exchange for retaining tech support while still using your own router.
All responses thus far are reading into things and answering questions that weren't asked and trying to do so with insufficient information.
"When I was changing my router my ISP technician told me that he has remote access to all routers provided by ISP. Was that true? If that is a fact it scares me..."
The appropriate response is "we don't know" (since we don't know who your provider is) but I'm sure this is the case. How are they going to manage their network to provide your connectivity if they don't have access to the device (their device) that they provided.
The question should be closed as too vague and not helpful.