How does Dynamic DNS provider work?

[George]

Am using WinXP, with a Linksys router on DSL modem. Would appreciate
insights into following questions, and any elaboration offered, thanks:

-Q1. When my ISP assigns a dynamic IP address...isn't that the address that
gets to the ROUTER, not the PC's behind it?Is the The public IP is the IP
address your ISP assigns you.
It can be either static, or dynamic.

-Q2. I'd like to set up remote access form my network and PC's while
traveling... Is it true that if I sign up with a Dynamic DNS provider, it
will eliminate the need to pay the ISP for a STATIC IP address? If so, is
there still some advantage of having the static IP address over a DNS
provider arrangement?

-Q3. Does using the Dynamic DNS provider mean that you are really accessing
an IP address (or name? like http://myprivatenetwork.com) on the provider's
equipment, and it in turn forwards you on to your own router and network?

-Q4. How could a DNS provider possibly know when your back-home IP address
changed, and what the new one was. If you have to install some code on your
PC to "sent up the IP address" periodically or whenever it changes...is that
really safe...could it be opening up port and sending up addresses that
could go awry or have malicious code that opens up your PC to someone?

-Q5. Could someone suggest some reputable/mainstream Dynamic DNS
providers...are there both free ones and fee-based ones, what would be the
difference, what would you recommend?

-Q6. Someone said that an ISP (with dynamic IP's) might could go months
without changing my IP address, but would for certain change it if I turn
the modem off and back on again, does that sound right? How can I tell what
my IP address is right at this moment? If you keyed that in now, what would
you see (request for password? nothing? my PC's files?)

Thanks,
George

 

[GTS]

SEE INLINE

Am using WinXP, with a Linksys router on DSL modem. Would appreciate
insights into following questions, and any elaboration offered, thanks:

-Q1. When my ISP assigns a dynamic IP address...isn't that the address
that
gets to the ROUTER, not the PC's behind it?Is the The public IP is the IP
address your ISP assigns you.
It can be either static, or dynamic.

Yes and yes.

-Q2. I'd like to set up remote access form my network and PC's while
traveling... Is it true that if I sign up with a Dynamic DNS provider, it
will eliminate the need to pay the ISP for a STATIC IP address?
Yes

If so, is
there still some advantage of having the static IP address over a DNS
provider arrangement?

Well, it's simpler. Otherwise not really.

-Q3. Does using the Dynamic DNS provider mean that you are really
accessing
an IP address (or name? like http://myprivatenetwork.com) on the
provider's
equipment, and it in turn forwards you on to your own router and network?

You could look at it like that but it's technically not quite accurate.
More precisely, the remote obtains your current IP through a lookup on the
name.

-Q4. How could a DNS provider possibly know when your back-home IP
address
changed, and what the new one was. If you have to install some code on
your
PC to "sent up the IP address" periodically or whenever it changes...is
that
really safe...could it be opening up port and sending up addresses that
could go awry or have malicious code that opens up your PC to someone?

As you surmised, you install a utility that informs the dynamic dns provider
when your IP changes. This functionality is built into some routers and can
be configured there. If the utility is from a reputable source, I wouldn't
be too concerned re. a security issue.

-Q5. Could someone suggest some reputable/mainstream Dynamic DNS
providers...are there both free ones and fee-based ones, what would be the
difference, what would you recommend?

http://www.dyndns.org/ is one good free one.

-Q6. Someone said that an ISP (with dynamic IP's) might could go months
without changing my IP address, but would for certain change it if I turn
the modem off and back on again, does that sound right? How can I tell
what
my IP address is right at this moment? If you keyed that in now, what
would
you see (request for password? nothing? my PC's files?)

Lease times vary between ISP's.

Turning your modem off for some interval is likely, but not certain, to
result in a new assignement depending how long.

To tell your external IP open http://checkip.dyndns.org/ or
http://www.whatismyip.com/ You can also see it in your router
configuration sreens.

 

[Jack]

Hi
May be this can Help: Home Server IP on the Internet:
http://www.ezlan.net/myip.html
Jack (MVP-Networking).

 

[George]

Thanks for assistance, wondered if someone could assist with these small
items.

-First, the http://www.whatismyip.com/ link works great and identifies the
(current) IP address coming into the router

-I entered http://205.xxx.xx.xxx and it brought up the login screen for the
router...I entered the password, it went to the ROUTER setup screen...great
for seeing things like LAN PC addreses (168.zzz.zz.zzz) MAC addresses
(01-90-A5-xx-yy-zz-xx), and other things, but I really want to get to my
PC's and their files behind the router

-Is this where port forwarding needs to be set up? There is a FORWARDING
tab that has these headings, apparently you can set up 10 different
forwards, for each one you have to enter:

CustomApps _________
ExtPort ___to___
Protocol TCP [ ]check box
Protocol UDP [ ]check box
IP Address 192.##.#.____
Enable [ ]

Was wondering what to set these to, and if there are any other things in
other TABs to set up

If I do FORWARD to say this PC I'm working on (let's say it's LAN IP is
192.166.34.150, then what happens after that, i.e.

Now a person on Internet keys in the WAN IP address...do they see files and
folders on this PC? a desktop on this PC?

By the way, if the ISP changes the IP address while accessing this PC, what
happens...does it just drop? Does a DNS provider keep the connection
up...or drop it also and then just let me know what the new IP address is?

Thanks,
George

 

[George]

There's also on the FORWARDING tab these two buttons, each of which has a
table with lots of pre-set things under then:

----UPnP Forwarding----
(has a list of changeable but pre-set things like Ext Port, Protocol (TCP or
UDP), Int. Port, IP address, [ ]enable, etc.

----Port Triggering----
Trigger port range __to___, incoming port range ___to___


What should I set for these, or just leave alone?

Thanks