I use Linux Mint 17.3 Rosa Cinnamon. My modem-router is a SmartAX MT882, very old but still working OK I think, which connects via an ethernet cable to my desktop computer. I neither want nor need wireless. I have an ADSL service via the telephone line.

When looking at the router set-up instructions for my ISP, I was surprised to see that there are only a few parameters to set up plus my username and password:
VCI - 38
VPI - 0
MTU - 1432
DNS - set to automatic or similar
Encapsulation - PPP over ATM using VC-MUX
Modulation type - auto
I do not understand what they mean, I am just repeating them like a parrot. I presume this is unrelated to the ethernet side of things.

The above contrasts with the about 273 lines of stuff that is currently in the configuration file of my modem-router, which can be seen in the thread "How to change the DNS server in Linux Mint, and should I?" Much of this could be the legacy of using Windows, when I tried a variety of security add-ons.

The two things that were mentioned a lot in Windows but have never been mention in Linux are ports and internet security zones. A large proportion of the config file appears to relate to these. I wonder if they are hampering my efforts to change the DNS server or throttling the download speed after a few seconds, so I would like to try starting clean again.

My questions are:

a) If I reset my modem-router to its factory settings, and adjust the factory-settings-config-file so that it includes the ISP parameters listed above, should Linux (and the firewall) be able to cope with it?

If it does go wrong, I hope I would be able to re-load my current config file to return the modem-router to its current state, but

b) is there much chance of getting bad changes to the computer which may be difficult to correct?

Thanks.

Just from what I know. the router is just a go between translator object.

it takes the phone line side (DSL) and gets an IP address On the other side ( for access, one or more PC) it gives each PC a IP address of there own.

Resetting it to factory should not affect anything, other then an IP Address that one or more PCs need to get past the router and onto the other side of it.

Setting your router to give out dynamic IP's is the easiest. Because whenever a PC logs in it automatically gets an IP (9 times out of 10, if not 10 out of 10) it will always be a different IP.



That matters not to the other side of router. That side will always have a static IP. This is how they trace you to point of origin. (for the most part)

Nevertheless, All you should need to worry about is getting your IP address. How you have your PC set up to accept an IP address.

If you are using Static IP which is an IP Address you specify then it has to match. If I remember correctly, in your Router settings and on your PC.

Dynamic IP (auto IP) your PC has to be set up to accept Dynamic IP's

thats it

you should see that it is actually rather simple whence you start to get your hands dirty.

Many of the settings that the ISP spoke of, and which you have listed here, are purely-technical ones which might be necessary to cope with their particular network infrastructure. "DNS" is not: it refers to domain-name resolution. (If an attached computer bounces a packet to its "default route," it will arrive at that router and be handled by it. The router runs a DNS server that queries the specified addresses.)

Routers often also run a DHCP service to assign addresses within your internal network. ("Giving out dynamic IPs.")

They also customarily act as DHCP clients with regard to the public (Internet) network, obtaining whatever public-IP your ISP doles out.

Your local computer(s), cell phones and such should simply see a local IP-network (usually 192.168.x.x) for which they can obtain an IP address using DHCP, and within which they can ask for "google.com" and find it. These services are customarily provided by your router according to these settings. That's usually the only thing that a client computer actually "needs to get from somewhere." Clients do not see the technical settings that might be needed to talk along your ISP's wire(less). They only perceive that they can reach LQ!

Therefore – reset the modem to factory settings (if necessary), set the settings that the ISP explicitly provides and says are important, and ignore the rest of it.

Only thing I ever set on my edge-device for DNS is
8.8.8.8
4.2.2.2
-------
Never Fail.

"When looking at the router set-up instructions for my ISP" where is this tidal wave of TMI?
Could boot a live CD of "LM 17.3 Rosa" and see how the device responds, or doesn't?

DNS resolution is generally the last thing I worry about, until it doesn't work. Then "Never Fail".
Mint is pretty polished and I'd be surprised it if your DNS issues on the device didn't work Out Of The Box,
or without intervention, maybe minimal.
It's working now? Why should LM 17.3 Rosa or "Linux" be any different?

I've hit restore defaults a couple of times on my device.
Access the panel, inhibit outside/remote access.
Set DNS.
Restart.


Defaults are good.
including /etc/resolv.conf on your LinuxBox.
I've never touched it.

I successfully did a factory-reboot, saved the factory-reboot config file, with a text editor changed one line in the config file to give my online username and password, and then loaded and saved the modified config file.

But I think I have got exactly what I had previously. The new config file is 293 lines just long like the old one, and downloads behave in exactly the same way as previously.

But at least it did not brick the modem-router as I feared, so I suppose this thread is Solved.

I will not try physically resetting the modem-router as no firmware downloads are available anywhere.

Glad it worked out!