How?
Perhaps an rc script?
Put an entry in /etc/rc.d/rc.local ?
That's what I do with things like that (TeamSpeak server, etc).
If it's a network thing, I'd put it in one of the network rc files. rc.local isn't run on every boot level.
It updates your dynamic IP to no-ip's central DNS server.
Putting it in your rc.network file would probably work best, but putting it in rc.local would be sufficient. You don't need sudo because startup commands are run as root anyways.
I'm not sure if you've tried any of that, because you were extremely vague. But if you have and it doesn't work, make sure you put the full path to the program (/usr/local/bin/noip2 or whatever), not just "noip2". Also make sure that noip2 goes straight into daemon mode, or figure out which flags you need for that, otherwise it'll slow down or lock up your boot.
Incidentally, ESR's "How To Ask Questions The Smart Way" (http://catb.org/~esr/faqs/smart-questions.html) might be something you should consider reading. Particularily the point, "Be precise and informative about your problem":
* Describe the research you did to try and understand the problem before you asked the question.
* Describe the diagnostic steps you took to try and pin down the problem yourself before you
(I realize that it's not a bug, but those still apply)
I was in an EXTREME hurry this morning, hence vagueness. *trys*
EDIT -
Uh, I don't have a /etc/rc.d/
joe@deadmeat:/etc $ ls
acpi debconf.conf gnome-vfs-2.0 ldap mime.types pcmcia screenrc
adduser.conf debian_version gnome-vfs-mime-magic ld.so.cache mkinitramfs perl scrollkeeper.conf
adjtime default GNUstep ld.so.conf mkinitrd php4 securetty
aliases defoma groff ld.so.hwcappkgs modprobe.d php5 security
aliases.db deluser.conf group lftp.conf modules pmount.allow services
alsa dev.d group- libao.conf modules.conf pnm2ppa.conf sgml
alternatives devfs gshadow libgda modules.conf.old popularity-contest.conf shadow
anacrontab dhcp3 gshadow- lilo.conf modutils postfix shadow-
apache2 dictionaries-common gtk links.cfg monopd.conf power shells
apm discover.conf gtk-2.0 locale.alias motd ppp skel
apt discover.conf-2.6 hal locale.gen mozilla-firefox prelink.conf sound
at.deny discover.conf.d hdparm.conf localtime mozilla-thunderbird printcap ssh
bash.bashrc discover.d host.conf logcheck mplayer profile ssl
bash_completion dpkg hostname login.defs mtab protocols sudoers
bash_completion.d emacs hosts logrotate.conf Muttrc python2.3 sysctl.conf
blkid.tab emacs21 hosts.allow logrotate.d mysql python2.4 syslog.conf
blkid.tab.old environment hosts.deny lsb-release nanorc qt3 terminfo
bluetooth esound hotplug ltrace.conf network rarfiles.lst timezone
bogofilter.cf evms.conf hotplug.d lvm NO-IPu5HriV rc0.d ucf.conf
bonobo-activation fam.conf hp lvmconf nsswitch.conf rc1.d udev
calendar fdmount.conf iftab lvmtab ODBCDataSources rc2.d updatedb.conf
cdrecord fonts imlib lvmtab.d odbc.ini rc3.d update-notifier
chatscripts foomatic inetd.conf lynx.cfg odbcinst.ini rc4.d vga
checkinstall fstab init.d magic oglerc rc5.d vim
console gaim inittab mailcap openoffice rc6.d vnc.conf
console-tools gconf inputrc mailcap.order opt rcS.d w3m
cron.d gdm iproute2 mailname orbitrc readahead wgetrc
cron.daily GeoIP.conf.default irssi.conf mail.rc pam.conf reportbug.conf X11
cron.hourly gftp issue manpath.config pam.d resolvconf xdg
cron.monthly ggi issue.net mdadm pango resolv.conf xlock.staff
crontab gimp jvm mediaprm paper.config rmt xml
cron.weekly gksu.conf jvm.d menu-methods papersize rpc xpdf
cups gnome kde3 mime-magic passwd samba
dbus-1 gnome-system-tools kernel-img.conf mime-magic.dat passwd- sane.d
You do have a rc(0-6)/(s).d though.
Oh. I thought you used Slackware for some reason. Maybe put it in one of those rc.# scripts, then? I think rc.0 is called upon shutdown, so don't put it in there. ;)
From that link:
QuoteBe precise and informative about your problem
* Describe the symptoms of your problem or bug carefully and clearly.
* Describe the environment in which it occurs (machine, OS, application, whatever). Provide your vendor's distribution and release level (e.g.: "Fedora Core 4", "Slackware 9.1", etc.).
* Describe the research you did to try and understand the problem before you asked the question.
You might want to read up on your particular distro and how to add stuff to the startup.
Why not, instead of posting a vague problem that nobody really understands quickly, wait until you have time to actually state it properly?