PSIgroup | Computing / ZeroConf

Resolving hostnames without DNS

Zeroconf
Bonjour Apple's incarnation of ZeroConf
Howl
the rpm was originally available from ATrpms repository
- mDNSResolver is used here, since it's part of the standard SL4
Avahi
nss-mdns
Plug-in module for nss-switch mechanism, so that you can ssh kwena.local
mdns-scan
rough test tool
http://cleanstick.net/jason/mdns-at-home.html

for Windows

please try Bonjour: Apple has released a version for Win.

install mDNSResponder:

yum install howl
service mDNSResponder start
chkconfig mDNSResponder on

Configure /etc/howl/mDNSResponder.conf like:

daq-pc _ssh._tcp local. 22

install nss-mdns

 yum install nss-mdns

In /etc/nsswitch.conf set:

hosts:          files wins nis mdns4_minimal [NOTFOUND=return] dns mdns4

In /etc/resolv.conf set:

search local physics.wits.ac.za wits.ac.za
nameserver 146.141.8.16
nameserver 146.141.15.210
nameserver 146.141.15.222

open the firewall

This will let the answers to the mDNS queries to be returned to your host IP. By default the fw (RH-Firewall-1-INPUT) accepts incoming requests to 224.0.0.251 (local broadcast).

 iptables -I INPUT 1 -s 146.141.41.0/24 -p udp --source-port 5353 -j ACCEPT
 service iptables save

test it

 service nscd stop
 time getent hosts vega
 service nscd start

Using ShMux, ssh-agent and Zeroconf

#!/bin/bash
# shm, a simple wrapper for ssh-agent and shmux

if [ -z "$1" ];then
  echo "Usage: $0 'shell commands'"
  exit 1
fi

#set -x
if [ -z "$SSH_AGENT_PID" ]; then
  eval $(ssh-agent)
  NEWSSHAGENT=1
fi
if ! ssh-add -l ; then
  ssh-add
fi

shmux -c "$*" \
admpsi@carina.local \
admpsi@proxima.local \
admpsi@rigel.local \
admpsi@sirius.local \
admpsi@vega.local 

if [ "$NEWSSHAGENT" ]; then
  eval eval $(ssh-agent -k)
fi

./shm "sudo yum -y clean metadata"
./shm "sudo yum -y install kile go4"
./shm "sudo yum -y clean all"