[olug] Cox is demanding DHCP

[David Walker]

Some hints to make DHCP less distasteful.

Use a variable in your firewall scripts for your own IP and some line to get 
your local IP address based on the name of your network adapter.
MY_IP=`/sbin/ifconfig eth0 | grep 'inet addr' | awk '{print $2}' | sed -e 
's/.*://'`

your /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
BOOTPROTO=dhcp
DHCP_HOSTNAME=cxYourCXNumber-d
ONBOOT=yes

your /etc/dhcpc/dhcpcd-eth0.exe
#!/bin/sh
/etc/rc.d/init.d/firewall restart| mail -s "Restarting firewall 
`hostname`" me at emailaddress.com
exit 0

Obviously your results will be different if you're using a different DHCP 
client.

My IP address has not changed in months (that was a real mess though, 
involving changing machine names too.  don't ask me why.  I have no idea)
so I haven't worried about it but you could consider the use of a service 
like http://www.no-ip.com/ to map your IP address to a non-changing DNS name.

In the 2 years I've had my service I do not believe my IP address has ever 
been changed by DHCP without their changing the computer name as well.

My past experience with other providers is that they were able to provide a 
static IP address but at a significantly higher cost.  The nature of cable 
modems makes it possible to have an IP address that very rarely changes with 
no extra cost involved.

On Friday 19 October 2001 01:38 am, you wrote:
> On Fri, Oct 19, 2001 at 01:02:45AM -0500, Dave Homan wrote:
> > I fail to see the drawback of running your computer dhcp.
>
> Depending on how you use your computer, there /can/ be several
> drawbacks to not having a definite, stable, IP address.
>
> [Snip.]
>
> > Or are you upset because you like to have access to your computer
> > remotely via ssh or telnet or (insert service here) and you can't do this
> > if the IP address keeps changing?  If this is the case then I should
> > probably point out that you can just as easilly gain access to your
> > computer using the computer name and domain name that they supply you? 
> > for example: Say I want to ssh into my computer from work so I can do
> > some homework.  I would then type  "ssh cx23984-y.omhan1.ne.home.com"
> > where cx2309480-y is my host name and omhan1.ne.home.com is my domain
> > name.  This will work just as good as "ssh 24.xx.xx.xx".  I live in the
> > north region of town (around dundee) so my domain is omhan1, however for
> > south I would imagine the domain
>
> That works great, until your IP address changes, and you find yourself
> unable to access your computer.
>
> It is true, most intelligent providers making use of DHCP set it up to
> attempt to repeatedly map the same IP address to your machine.
> However, when you're using DHCP you lose the certainty that your IP
> address will remain the same.
>
> [Snip.]
>
> > I honestly can't think of any other reason why you would need a static ip
> > over a dynamic ip for regular residential service.  if you absolutely
> > need a static ip and there is no way around it then I suggest you shell
> > out lots and lots of $$$ per month and get a t1 line or something.
>
> For someone who simply requires the ability to access their home
> computer remotely, this seems excessive at the least, if not absurd.
>
> > At any rate, I honestly don't think there is any other way to run a tcp
> > network with over 30,000 subscribers and spread out across an entire city
> > using any other method other than  (or a protocol similar to) dhcp.
>
> It's not at all difficult to set up a large network making use
> primarily of DHCP but limited use of static IP assignments, as well.
> With most DHCP setups, it's even possible to permanently map an IP
> address to a specific MAC address.  Or, depending on your setup, if
> you're using local addresses internally which are mapped to real IP
> addresses through a firewall, it's possible to set up a conduit between
> the two IP address.  Lastly, with most Cable modem setups, each cable
> modem has a MAC and IP address, as well, giving you an easy way to set
> things up.
>
> There's really no good excuse for blowing people off when they make a
> fairly legitimate request for a service.
>
> > But if you're still adamant about how cox is "screwing" you somehow then
> > maybe you should go back to dial-up.
>
> If the goal is making your computer accessible remotely, this would
> seem to do little towards acheiving that goal.
>
> > just trying to understand,
> > -dave

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