IPPP(4) Kernel Interfaces Manual IPPP(4)
ippp -- ISDN synchronous PPP network driver
pseudo-device ippp count
The ippp driver interfaces the IP subsystem of the operating system with
the ISDN layer so that a transport of IP packets over an ISDN link is
For configuration of the ippp driver, either the ipppctl(8) utility is
used or it is configured via isdnd(8) and its associated isdnd.rc(5)
In case an IP packet for a remote side arrives in the driver and no
connection is established yet, the driver communicates with the isdnd(8)
daemon to establish a connection.
The driver has support for interfacing to the bpf(4) subsystem for using
tcpdump(8) with the ippp interfaces.
The ipppctl(8) utility is used to configure all aspects of PPP required
to connect to a remote site.
LINK0 and LINK1
The link0 and link1 flags given as parameters to ifconfig(8) have the
following meaning for the ippp devices:
link0 Wait passively for connection. The administrative Open event to
the Link Control Protocol (LCP) layer will be delayed until after
the lower layers signal an Up event (rise of ``carrier''). This
can be used by lower layers to support a dial-in connection where
the physical layer isn't available immediately at startup, but
only after some external event arrives. Receipt of a Down event
from the lower layer will not take the interface completely down
in this case.
link1 Dial-on-demand mode. The administrative Open event to the LCP
layer will be delayed until either an outbound network packet
arrives, or until the lower layer signals an Up event, indicating
an inbound connection. As with passive mode, receipt of a Down
event (loss of carrier) will not automatically take the interface
down, thus it remains available for further connections.
The link0 flag is set to off by default, the link1 flag to on.
bpf(4), isdnd.rc(5), ipppctl(8), isdnd(8), tcpdump(8)
The ippp device driver was written by Joerg Wunsch <joergATfreebsd.org>
and then added to ISDN4BSD by Gary Jennejohn <garyATfreebsd.org>.
This man page was written by Hellmuth Michaelis <hmATkts.org>.
NetBSD 6.1.5 August 31, 2000 NetBSD 6.1.5