[GLLUG] Networking question

Tue Dec 13 23:33:49 EST 2011

Just a thought, 
check the TTL(Time to Live) on your IP address if you have a DSL/Cable account. Often those IP address pretty much stick to the same one and have like a month TTL with some providers. If your IP address does not change very often then using ssh to get back to your server/workstation should not be much of a problem. Also, I am assuming that your provider assigns you non- RFC1918 address space (stuff like 192.168.x.x, 10.x.x.x, 172.16.x.x) some smaller (and some bigger) ISPs use that address space and NAT to same IP space when giving address to client. 

If you on a provider that keeps a low TTL you still will most likely end up with the same IP address if you do not power cycle your router much. DHCP will "usually" give you the same IP address you request when updating your IP lease. 

In the end, if it is really a problem a Dynamic DNS provider is the correct solution imho. I have not used one, but I know they are out there, as other posters here have noted. 

To get your TTL lease time on a DHCP lease most linux systems write that to the daemon.log file in /var/log 

example:

Dec 13 23:24:22 forseti dhclient: DHCPREQUEST on eth0 to 172.16.5.35 port 67
Dec 13 23:24:22 forseti dhclient: DHCPACK from 172.16.5.35
Dec 13 23:24:22 forseti dhclient: bound to 172.16.5.41 -- renewal in 279 seconds

Here you can see my lease will be up in 279 seconds. My lease is under my control and I have a very short lease. If you poke around your logs you can usually see pretty quickly your lease time. I believe that "Network Manager" can also display your lease life but honestly I am not seeing it on my version of Debian. I hope this helps.

Cheers!

Tad

On Sun, Dec 11, 2011 at 09:51:52PM -0500, Charles Ulrich wrote:
> Hi Taylor,
> 
> Who's your domain name registrar? Some of them come with free DNS
> hosting and this can include dynamic DNS. I use namecheap.com and they
> have a simple API for doing dynamic DNS updates. (I don't bother with
> it though, because my IP never changes unless my router's been offline
> for a length of time.)
> 
> Charles
> 
> On Sun, Dec 11, 2011 at 9:03 PM, Richard Houser <rick at divinesymphony.net> wrote:
> > I use then on domains I own, and ODS happens to charge $20 a year for
> > up to five private domains. ?Other services are in roughly the same
> > ballpark, but I hit a few duds with regard to uptime and support
> > before I found ODS. ?It works just like a traditional static DNS host.
> > ?You just need to point your registrar to your DNS provider's DNS
> > servers.
> >
> > It it's just for you, and you really, really want to go on the cheap,
> > you could just setup your DDNS tool or a script to email you the new
> > IP. ?I used to do that before I found a DNS host I was happy with.
> >
> > On Sun, Dec 11, 2011 at 8:27 PM, Karl Schuttler
> > <karl.schuttler at gmail.com> wrote:
> >> Since you say you have a router that supports dynamic dns, but don't
> >> understand how it fits in to your problem scenario, i think you dont
> >> understand how dynamic dns works or what it does.
> >>
> >> Typically, you set up an account with a dynamic dns provider, who
> >> issues you a domain (ala karl.dyndns.org) and download or configure
> >> (on your router) a dynamic dns client. As your IP changes, the client
> >> will phone home to the dynamic dns provider and tell the provider what
> >> your new IP address is, and the provider will update their dns record
> >> for your domain (karl.dyndns.org).
> >>
> >> I've never messed with domain registrars and getting a dynamic dns
> >> provider to update a purchased domain, rather than their own
> >> subdomains (e.g., they will update karl.dyndns.org, but I don't know
> >> about getting them to update karlrules.com). As it seems this isn't a
> >> critical website that needs to be super-professional, you might just
> >> have your purchased domain (e.g. karl.com) forward to the dynamic dns
> >> domain (karl.dyndns.org).
> >>
> >> On Sun, Dec 11, 2011 at 8:01 PM, Richard Houser <rick at divinesymphony.net> wrote:
> >>> Just use a dymamic dns provider.? Personally, I use ods.
> >>>
> >>> On Dec 11, 2011 7:35 PM, "Taylor Burke" <tburke1192 at gmail.com> wrote:
> >>>>
> >>>> Alright, I've got an interesting scenario for you guys. Since I'm not
> >>>> that good at networking fundamentals, I figured I'd ask people who
> >>>> are.
> >>>>
> >>>> I've got a domain name and a server at home running Arch Linux that I
> >>>> want to be able to SSH into from {work,school,etc}. At home I have a
> >>>> router that has support for dynamic DNS and I'm aware of No-IP and
> >>>> DynDNS, but I'm trying to figure out how that's gonna fit into my
> >>>> situation. The issue is, my ISP charges $15 for static IPs and I
> >>>> really can't justify that right now, and I believe it was a monthly
> >>>> fee. So, do you guys have any clever workarounds I could try? Lemme
> >>>> know if anything needs clarification.
> >>>>
> >>>> Regards,
> >>>> Taylor
> >>>> _______________________________________________
> >>>> linux-user mailing list
> >>>> linux-user at egr.msu.edu
> >>>> http://mailman.egr.msu.edu/mailman/listinfo/linux-user
> >>>
> >>>
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-- 

Thomas Driscoll
e-mail: tad001 at sunn.net
cell phone:(517)944.2041

Philosophy is a battle against the bewitchment of our intelligence by means of language.

         by: Ludwig Wittgenstein