Dynamic IP addreses

Hello all:),
I have a DSL with a dynamic IP connected to a linksys router. I am trying to figure out how to setup a simple linux web server behind this setup. The IP seems to rotate between a list of 3 or 4 different numbers each time it reconnects. I poked around here but couldnt find a thread which dealt with this so I thought I would ask.

I have looked into serviced like dynip which will solve the dynamic IP problem, but it forces me to leave a port open for them. I am woundering if there are any known problems with this type of setup? My gut feeling tells me leaving any ports open is a possible hole. Is there a way to secure it?

I am also woundering if there is a better and safer way to link my domain to my linux box over the dynamic DSL?

Thanks for you time
Ruffasdagut

I seriously doubt that the Dyndns client requires any sort of tcp port open. As it is your only solution, I wouldn't really worry too much.

Your best bet would be to do the following:

1: on your linksys router, have it set up for static IP address (DHCP off) and obtaining the dynamic IP from your ISP. This will allow you to set up your own IP network internally.

2: assign static IP addresses for each of your machines internally. I suggest sticking with the default that the linksys router uses, and that's 192.168.1.x (up to 253 clients). The router would be 192.168.1.1, the machines could start at 192.168.1.100, 101, 102, etc.. Also, set your windows machines gateway to 192.168.1.1 as well as setting up DNS on your Windows machines (put in whatever your ISP gave you).

3: in the port-forwarding section of your router (it's in the advanced tab I believe), have all port 80 traffic that hits your router sent to whatever IP address you assigned to your linux box.

4: go to www.dyndns.org , register, and have a "name" set up for you and friends to use. Something like "mymachine.homeip.net" and have it mapped to your dynamic IP address. Downside to this is that every time your lease expires and it renews a different one, you'll have to go to this site again and change it. They do 15 minute updates so it's pretty fast. Otherwise you're all set to go.

5: if dyndns.org works for you, please donate (as I've done) to help support the services they provide for free.

Hope this helps.

wait a minute, if you have a router getting and IP address via DHCP from you ISP, how does leaving a port open for your dynamic DNS supplier help. If they have to connect to you, leaving a port open for them will not help at all, after your outside IP has changed....

unless the port is left open only so that they can verify that your server is what it claims to be, after the IP change, when your server has notified them of it. or something.

In that case, it shouldnt be too hard to set up a linux router/firewall which gets its external IP via dhcp, and allows inbound traffic on the port they require from "only"the IPaddresses that they use.

I would need to take a couple hours to play with this, but, I am sure it is not too difficult. If I had the time it is interesting enough that I might try it just for fun...

You could also just try asking your ISP for a static IP. They may try to make you pay for that, but some will not and just assign you one. If your dynamic is only jumping between 4 different address anyways, you could probably just use one of those and not have a problem.

I went with DHS.org for my dhcp website hosting. You just register with them, go to tucows and get a script for auto updating, and every time you go online, within 10 min or so, the dns is updated to reflect your new ip address. Im not running through any sort of router, just a firewall/masqing box.

have you tried no-ip.com / no-ip.org ??