---
name: "nrprobenet"
section: "8"
platform: "linux"
package: "nfsroot"
version: "0.5"
release: "Debian 1.3 (Bo)"
platforms: ["linux"]
url: "https://new.carta.tech/nrprobenet"
---

# nrprobenet(8)

probe local net for hw/IP pairs

## NAME

nrprobenet - probe local net for hw/IP pairs

## SYNOPSIS

**update-menus \[-v\] \[-s\] \[-i time\] \[-nodir\] \[-p port\] \[-c count\] \[-u time\] -r IP-IP \[-r IP-IP ...\]**

## DESCRIPTION

Nrprobenet pings host on the (usually local) network, and collects data from /proc/net/arp, building tables to map ethernet numbers into IP adresses. Whenever the tables change, (optionally) writes a /etc/bootptab file to reflect the changes, and (optionally)  creates tftpboot directories for new hosts found.

It can also log changes that normally shouldn't happen to syslog (i.e., an ethernet card that changes IP number, or a IP number that suddenly uses a different ethernet card).

## OPTIONS

- \-v

  Verbose output. Shows whatever host it's pinging, or not pinging, and for what reason.

- \-r x.x.x.x-y.y.y.y

  Ping sequentially IP numbers x.x.x.x through y.y.y.y (the -r option may be given any non-zero number of times)

- \-u time

  If time is non-zero, nrprobenet will write the /etc/bootptab file every time seconds (if anything changed in it, that is). Also, unless you give the  **-nodir** option, it will execute mknfsroot for each new host.

- \-i time

  Wait time seconds between each ping (default: 1)

- \-c count

  Stop after count rounds though all the IP ranges (see  **-r** ) (default: -1=dont't stop)

- \-p portnr

  Use port p (default: 7=echo)

- \-nodir

  Do not make the /tftpboot directories. If you specify the -u option, the /tftpboot/$IP directories are usually created using the  **mknfsroot** script, unless you give the **-nodir** option.

- \-s

  Log "suspicious" IP/hw changes to syslog (i.e. an ethernet card that suddenly changes IP number, or  a IP number that uses a different ethernet card)

## NEEDED

An nslookup that accepts one parameter (the hostname/IPnumber to lookup). The debian bind package does contain such a nslookup script.

## USAGE

Usually, when you install the nfsroot package, everything is setup correctly, except for the "probenet=0" line in /etc/init.d/nrprobenet. Change that to "probenet=1" and you're set (start the programme with "/etc/init.d/nrprobenet start"). Before you do that, however, you should make sure there is enough diskspace on the directory that /tftpboot lives on (about 3--10M).  If there isn't, it's usually the easiest to create a symlink from  /tftpboot to /mnt/bigdisk/tftpboot. And, you may want to check whether the default network range is OK (type "source /etc/nfsroot/def; echo $IPRANGE" to find out)

## FILES

- */etc/nfsroot/ignorehosts*

  What hosts to ignore (don't ping them). This file contains regular expressions; any hostname that matches any regular expression in this file will be ignored.

- */etc/bootptab*

  The file to write the bootptab stuff to, only if **-u** option is given

- */etc/nfsroot/bootptab*

  The /et/bootptab file is created by first copying this file, and then appending the data obtained. This way, you can specify bootpd stuff for the clients.

- */var/lib/nfsroot/arplist*

  List of all IP/hw numbers found. This is read in on startup, and written whenever new hosts are found.

- */proc/net/arp*

  The kernel-supplied file with recent ARP data in it.

- */var/run/bootpd.pid*

  Whenever the /etc/bootptab data changed, nrprobenet tries to SIGHUP the bootpd, to make it re-read the config data. The pid of bootpd is taken from this file.

## BUGS

Does not know what to do with hosts with more than one IP number (ip forwarding).

## DISTRIBUTION

Distribution is subject to the GNU public license.

## AUTHOR

Joost Witteveen \<joostje@debian.org\>, \<joostje@cistron.nl\>

## SEE ALSO

**mknfsroot**