---
name: "i4bisppp"
section: "4"
platform: "linux"
package: "freebsd-manpages"
version: "6.0-5"
release: "Debian 4.0 (Etch)"
platforms: ["linux"]
url: "https://new.carta.tech/i4bisppp"
---

# i4bisppp(4)

isdn4bsd synchronous PPP over ISDN B-channel network driver

## NAME

**i4bisppp** – isdn4bsd synchronous PPP over ISDN B-channel network driver

## SYNOPSIS

**device** **"i4bisppp"** \[count\] **device** **sppp**

## DESCRIPTION

The **i4bisppp** driver interfaces the IP subsystem of the operating system with the isdn4bsd package so that a transport of IP packets over an ISDN link is possible.

The driver is just a glue layer between the [sppp(4)](/sppp/4.md) backend and the ISDN4BSD package and needs the [sppp(4)](/sppp/4.md) driver configured into the kernel.

The network interfaces provided by this driver are named *isp\<n\>*, where \<n\> is a number between 0 and count-1 from the kernel config line.

For configuration of the i4bsppp driver, either the spppcontrol(8) utility is used or the driver can be configured via isdnd(8) and its associated isdnd.rc(5) file.

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)](/bpf/4.md) subsystem for using [tcpdump(1)](/tcpdump/1.md) with the **isp** interfaces.

## LINK0 and LINK1

The *link0* and *link1* flags given as parameters to [ifconfig(8)](/ifconfig/8.md) have the following meaning for the *isp\<n\>* devices:

- link0

  wait passively for connection

- link1

  auto-dial on output

The *link0* and *link1* flags are set to *off* by default.

See [sppp(4)](/sppp/4.md) for a more detailed discussion of the flags.

## SEE ALSO

[tcpdump(1)](/tcpdump/1.md), [bpf(4)](/bpf/4.md), [sppp(4)](/sppp/4.md), isdnd.rc(5), isdnd(8), spppcontrol(8)

## AUTHORS

The **i4bisppp** device driver was written by Joerg Wunsch ⟨joerg@FreeBSD.org⟩ and then added to ISDN4BSD by Gary Jennejohn ⟨gj@FreeBSD.org⟩.

This manpage was written by Hellmuth Michaelis ⟨hm@FreeBSD.org⟩.