First of all, you need to setup your ircd to directory, that can be accessed by normal user. Best choise - to create special user and group (for example user and group named "ircd")
create the directory to setup ircd to.
create special user and group for ircd:
groupadd ircd -g 10000
useradd ircd -u 10000 -g ircd -s /bin/bash -M
change owner of directory to newly created user/group, and set correct permissions:
chown ircd:ircd /usr/local/ircd
chmod 0750 /usr/local/ircd
then to create new session, type from root:
su - ircd
then download sources and install ircd as usually to /usr/local/ircd
Error binding socket tp IP 100.*.*.*** port 6667 IRC.node.com: Address already in use
this error means that some daemon already listening on port 6667.
you can find it by typing something like
netstat -apn | head -n 2 && netstat -apn | grep LISTEN | grep 6667
if you want to terminate daemon that listening on port 6667, you can do something like
kill -15 12345
where 12345 - PID, that you see in netstat output.