I used to launch my dialup sessions manually via a batch file. I had a
link on the desktop that pointed to a file named internet.bat which
contained a sequence of Start commands that would launch all my
Internet apps, eg firewall, email client, news client, browser, and of
course my dialup connectoid. The batch also checked whether my other
PC was currently on the LAN, in which case the dialup session did not
go ahead.

To set up something like the above, you need to first prevent your
apps from automatically connecting to the Net. To launch the dialup
session, you could use a batch command such as ...

start your_ISP.lnk

... where the .lnk file is a shortcut to your DUN connectoid.

To test whether a dialup session is in progress, you could test for
the presence of the rnaapp task. Microsoft's Win98 Resource Kit has a
tlist.exe command line utility that lists all the running tasks. You
could use the following commands to test for rnaapp:

tlist | find /i "rnaapp" > nul
if errorlevel 1 echo Dialup Networking is not running

Tlist.exe is available here:
ftp://ftp.microsoft.com/Services/TechNet/samples/ps/win98/reskit/DIAGNOSE/TLIST.EXE

FYI, you can also kill running tasks using the kill.exe utility:
ftp://ftp.microsoft.com/Services/TechNet/samples/ps/win98/reskit/DIAGNOSE/KILL.EXE

BTW, my internet.bat routine also displayed the more important entries
in the most recent firewall log, in particular any outgoing alerts.
The batch also analysed the modem's last call statistics which alerted
me to any problems with my phone line. The modemlogs and ppplogs were
searched for any errors, eg buffer overruns, CRC errors.

- Franc Zabkar