Does OS/2 automatically fall back to Secondary DNS when the Primary fails to 
respond, due to perhaps a DOS attack or physical failure?

I am too often unable to Browse or get Mail, yet Time, Ping and IPTV are 
working.  Perhaps the last 3 don't use the same protocol as the first 2?

No amount of rebooting router or PC made any difference.
Some of the, usually useless, advice blamed authentication with my ISP.
I suspected my ISP's DNS, but until I changed the primary address in tcpcfg and 
everything worked immediately without any rebooting, did I question the presumed 
facility of automatic fallback.

On Fri, 2 Dec 2016 19:49:00 UTC, johnsuth@nospam.com.au wrote: 

> Does OS/2 automatically fall back to Secondary DNS when the Primary fails to 
> respond, due to perhaps a DOS attack or physical failure?

Yes. Thats what it is there for.

> I am too often unable to Browse or get Mail, yet Time, Ping and IPTV are 
> working.  Perhaps the last 3 don't use the same protocol as the first 2?

I don't really know, how many DNS's OS/2 actually support. Some OS's only support 2.

> No amount of rebooting router or PC made any difference.
> Some of the, usually useless, advice blamed authentication with my ISP.
> I suspected my ISP's DNS, but until I changed the primary address in tcpcfg and 
> everything worked immediately without any rebooting, did I question the presumed 
> facility of automatic fallback.

You can easily test name lookups with the host command.
Changing nameservers is just a question of editing MPTN\ETC\RESOLV2 file.

An alternative nameserver you can try is Googles 8.8.8.8

-- 
  Allan.

It is better to close your mouth, and look like a fool,
than to open it, and remove all doubt.

Hi John, Allan,

> I don't really know, how many DNS's OS/2 actually support.
> Some OS's only support 2.

I've only ever used two in the past before swapping to BIND.BIND setup

> > No amount of rebooting router or PC made any difference.
> > Some of the, usually useless, advice blamed authentication with my ISP.
> > I suspected my ISP's DNS, but until I changed the primary address in tcpcfg and 
> > everything worked immediately without any rebooting, did I question the presumed 
> > facility of automatic fallback.

DNS can do weird things sometimes, make sure you have both UDP
and TCP ports 53 open.

> You can easily test name lookups with the host command.
> Changing nameservers is just a question of editing MPTN\ETC\RESOLV2 file.

If you have older programs, copy RESOLV2 to RESOLV. Make
sure that if you are using DHCP that the RESOLV2 file isnt
overwritten.

Cheers