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static ip

Started by CSWizard, 2005-09-29T00:09:06-05:00 (Thursday)

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Does anyone know how or if I can set up a static ip address without having to ask my isp to give me a static ip? I thought I set it up once a long time ago, but I can't remember. :-?

Peter Motyka

This is not a very good idea.  Many moons ago, when I lived in the SIUE dorms, I hard wired the IP address of my system using the 'Network Connection' manager in Windows or ifconfig in Linux.  The address I used also happened to be withing the DHCP scope for the network I was on.  When you hard wire the address, the DHCP server has no idea that this address should be ineligible for assignment to other network hosts.  The DHCP server will likely attempt to issue this address to another client, resulting in either you or the other client being unable to access the network due to an IP address conflict.  If this happens often, I suspect OIT (or another ISP) would be able to find a machine that has a hard wired IP address by the lack of a valid DHCP lease associated with the statically configured host.  In my experience, ISPs don't like that type of network meddling...  If your ISP offers static address (mine does for an extra 5.00/mo and it is well worth it) take advantage of it.
SIUE CS Alumni 2002
Grad Student, Regis University
Senior Engineer, Ping Identity

Matthew Thomas

Don't even bother paying... Just get a dyndns.org account.
This service is free and gives you a static name to remember instead of an ip address. That name then re-directs to your ip, as was last updated in their system. Updater clients are free.

For if you have dial-up (or your ip could potentially change more than once in a day)

if your ip does not change that often.

Superman wears Jack Bauer pajamas


I personally use no-ip client.  You just download the client, signup on teh site what you want your domain to be (it'll end up being whateveryouwant.no-ip.com) and then the client runs in the system tray and checks every so often to see if it needs to change your IP record.  It's great because I can remote desktop windows machines, ssh in, do a ton of stuff remotely.

www.no-ip.com I believe
Bryan Grubaugh
Quickly aging alumni with too much time on his hands
Business Systems Analyst, Scripps Networks.

Peter Motyka

QuoteMatthew wrote:
Don't even bother paying... Just get a dyndns.org account.

Well, it depends on what your needs are.  I host my personal domain (motyka.org) from home and depend on this static address for email, http(s), etc.  As far as mail is concerned, if you attempt to host an email server from a cable modem (or other DHCP-based ISP) you will likely have a client1232342.blah.blah.comcast.net or other hostname indicative of a dynamic address.  This is a problem when you try to send email from a server parked on such an IP.  Most email servers will refuse messages from DHCP hosts because they are the source of the majority of spam on the Internet.

Another reason is reverse DNS.  If your ISP is *cool* they will also let you alter the PTR record of your static IP.  For example:

nslookup motyka.org

nslookup name = eudora.motyka.org.

Note, the PTR record is NOT dsl234.dhcp.qwest.net, like it was prior to my signing up for a static IP.

So, it depends on what your needs are.  If you are simply looking for an easy to remember symbolic hostname, yeah dydns will work just fine.  If you want to host a mail server, get a static IP and make sure you can alter the associated PTR record.
SIUE CS Alumni 2002
Grad Student, Regis University
Senior Engineer, Ping Identity