network settings get changed unintentionally
 

I use my pc with Debian at 3 locations, they all have different isps. So each one has its configuration for dns and these are all different and are set up in the ethernet configuration. Often the configuration gets changed without warning and suddenly the browser halts. What can I do about it please? I would really appreciate helpful suggestions

Sorry i'm having some difficulty understanding the question, what is changing?

The DNS server entries are stored in /etc/resolv.conf

Do you mean the DNS servers IP changes or you/Debian changes physical NIC info? (As viewed/changed with ifconfig command)

You may want to look at the switchconf or laptop-net packages.

I think I know what your saying. The problem is that your resolve.conf file is getting "reset" therefore your nameserver setting is getting reset.

To keep this from happening set the immutable bit like so:

dns reset
 

Thanks to Dave, Happy Tux and Bullium, I probably didn't explain it very well but Bullium has hit the right spot. I'll do what he says and will keep in touch. Very many thanks to you all.
Frank

network changes
 

Thanks very much , all is ok now!