ppp -auto

[Igor Zbirka]

I would like to ask you for help. In manpages for ppp (8) is written:
"The following modes are understood by ppp:
-auto
	ppp opens the tun interface, configers it then it goes into the
beckground. The link isn't brought up until outgoing data is detected on the
tun interface at which point ppp attempts to bring up the link."

I've just installed FreeBSD 5.2 on my compaq deskpro. I've used the 'User'
option of the distribution (Average user - binaries and doc only).
I've read and go through all the man pages regarding to ppp and my modem is
conecting without any problem. I can go online and do all what I need.
 BUT!!!:)  when I write 'ppp -auto install' it automaticaly dials into ISP. So
according to man page (as I've qouted on the begining) it means that there were
detected datas on the tun interface. My question is what it is. I'm asking this
because I wasn't sending anything and the modem was online for more than 6
minutes, something was going on, and than I've switched it off manualy. In my
ppp.conf (as it is attached) I've set timeout 120. When I did ping, after it
finnished exactly in two minutes. 
So what I want is that only when
I'm sending email or browsing any web page it will go online. 
Do you have any idea what
should I do and why there are some datas which are on the tun interface.
Is a firewall soulution?

Thanks a lot

Igor Zbirka

-----------------------------------
My ppp.conf file:

default:
 set öog Phase Chat LCP IPCP CCP tun command
 ident user-ppp VERSION (built COMPILATIONDATE)

 set device /dev/cuaa0
 set speed 115200
 set dial "ABORT BUSY ABORT NO\\sCARRIER TIMEOUT 5 \
             \"\" AT OK-AT-OK ATE1Q0 OK \\dATDT\\T TIMEOUT 40 CONNECT"
 set timeout 180
 enable dns

install:
 set phone xxxxxxxxx
 set authname xxxxxxxxxxxxx
 set authkey xxxxxxxxxxxx
 set speed 115200
 set device /dev/cuaa0
 set ifaddr 0 0 255.255.255.0 0.0.0.0
 add! default HISADDR
 set timeout 120
 enable dns
 set log local phase