I'm pretty sure that "ppp" is what you need:
iago@Slayer:$ sudo slapt-get --show ppp
Package Name: ppp
Package Mirror:
ftp://ftp.slackware.com/pub/slackware/slackware-10.0/--search ppp
Package Location: ./slackware/n
Package Version: 2.4.2-i486-2
Package Size: 418 K
Package Installed Size: 1130 K
Package Required:
Package Conflicts:
Package Suggests:
Package MD5 Sum: 3468f1c559e761f3895f888710bcfebe
Package Description:
ppp: ppp (Point-to-Point Protocol)
ppp:
ppp: The Point-to-Point Protocol (PPP) provides a method for transmitting
ppp: data over serial links. It's commonly used for connecting to the
ppp: Internet using a modem. This package includes the PPP daemon (pppd),
ppp: which negotiates with the peer to establish the link and sets up the
ppp: ppp network interface, and pppsetup, an easy-to-use utility for
ppp: setting up your PPP daemon.
See if you can find an Ubuntu version?