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Bill Crocker
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 Posted: Sat Sep 23, 2006 7:15 pm Post subject: Dynamic vs Static I/P with Comcast? |
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Is Comcast assigning everyone static I/P addresses these days? I live in
Macomb, Michigan and I've had the same I/P address for a very long time now.
Powering the cable modem off, and on does not force a change...even if I
leave it off for several hours. Is there a way to force a new I/P address?
Thanks,
Bill Crocker |
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Bit Twister
Guest
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| Posted: Sat Sep 23, 2006 8:42 pm Post subject: Re: Dynamic vs Static I/P with Comcast? |
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On Sat, 23 Sep 2006 10:15:55 -0400, Bill Crocker wrote:
| Quote: | Is Comcast assigning everyone static I/P addresses these days?
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Yep, not likely to change unless your cable segment gets congested and
they decide to split your segment. You address might change if you
wind up on the new split side.
| Quote: | I live in
Macomb, Michigan and I've had the same I/P address for a very long time now.
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Why would you want to change it. I like the almost static address so
I can use it to kill file morons in Usenet posts.
| Quote: | Powering the cable modem off, and on does not force a change...even if I
leave it off for several hours.
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Yep, looking at my dhcp lease from comcast here in Dallas.
Obtained Fri Sep 22 22:41:58 CDT 2006
Renewal 2006/9/24 19:29:26;
Rebind 2006/9/26 15:41:56;
Expires 2006/9/27 03:41:56;
I would have to leave it off past the expiration date to have a ghost
of a chance of loosing it. Then several other people would have to
leave theirs off for the same period or a bunch of new customers would
have to get added to my segment to force the dhcp server to re-use my
expired address. Not much chance of that.
| Quote: | Is there a way to force a new I/P address?
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Buy a new interface card and connect it to the cablem modem. |
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John Gray
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| Posted: Sat Sep 23, 2006 10:30 pm Post subject: Re: Dynamic vs Static I/P with Comcast? |
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"Bill Crocker" <wcrocker007@comcast.net> wrote in
news:c_qdnenn1KYx3IjYnZ2dnUVZ_vCdnZ2d@comcast.com:
| Quote: | Is Comcast assigning everyone static I/P addresses these days? I
live in Macomb, Michigan and I've had the same I/P address for a very
long time now. Powering the cable modem off, and on does not force a
change...even if I leave it off for several hours. Is there a way to
force a new I/P address?
Thanks,
Bill Crocker
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If you have a NAT router, change the internet(WAN) MAC address of it.
That always changed the IP I was assigned by RR. If I changed it back a
week later, I got the previous one that I had for 5+ years. I liked the
"static" IP. However, recently RR reconfigured this area and I now have
a new IP in a different range, and so far it's holding static. Comcast
may do the same.?? You will probably have to power down the cable modem
for a couple of minutes for the new IP to be acquired. |
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Warren
Guest
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| Posted: Sat Sep 23, 2006 11:16 pm Post subject: Re: Dynamic vs Static I/P with Comcast? |
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Bill Crocker wrote:
| Quote: | Is Comcast assigning everyone static I/P addresses these days? I live
in Macomb, Michigan and I've had the same I/P address for a very long
time now. Powering the cable modem off, and on does not force a
change...even if I leave it off for several hours. Is there a way to
force a new I/P address?
|
You're describing the very nature of any fixed network, whether it uses
static IP's or DHCP. IP addresses will not change unless there is a need
for them to change.
The difference is that when using DHCP, the changes that need to occur
happen automatically. With static IP's, when changes have to be made,
someone has to manually make them, and make them during the right time
window. That's not practical when so many pieces of equipment are located
inside thousands of private residences.
Even with DHCP, your IP address does not change unless it has to. The DHCP
server will continue to give out the same IP addresses to the same
equipment as long as it's possible. Disconnect and reconnect as many times
as you want, but you'll continue to get the same IP address. It won't
change until there is a network reconfiguration that requires a
renumbering.
This differs from dial-up. With dial-up, if you disconnect, and reconnect
you are, depending on how busy things are, likely to get a different IP.
That's because the fixed part of the network ends at the modem rack. At
the PoP there will be a rack with, let's say, 64 modems on it. The first
call to the access phone number goes to the first modem in the rack, the
second call to the second modem, etc. And when someone disconnects, the
next person to call in fills that empty space. So at a busy PoP, each time
you dial-in, you'll get a different modem. In a network like this, they
only have enough IP addresses to give each modem an IP address, not each
possible user who might connect to the modems. So the IP address you'll
get will depend on which modem you connect to.
With a cable internet system, theoretically everyone is always connected,
so there must be enough IP addresses for each user. All IP addresses will
always be in use. There's absolutely no reason to vary from normal
networking practices of the DHCP server always giving the same IP address
to the same equipment. That's the way DHCP normally works, and there's no
need to confuse things by randomly juggling IP addresses around.
Essentially, whether you configure things by DHCP or manually, IP
addresses should not change unless they need to. Using DHCP just means
someone doesn't have to make a manual change to each piece of equipment.
DHCP allows any change to be transparent to the end user. That's it. It
does not mean your IP address will change. It only means that if it has to
change, you won't be required to make the change manually on your end at a
prescribed time.
--
Warren H.
==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.
Power Lawncare Tools for Spring Clean-up:
http://www.holzemville.com/mall/blackanddecker/ |
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Andrew Rossmann
Guest
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| Posted: Sun Sep 24, 2006 6:31 pm Post subject: Re: Dynamic vs Static I/P with Comcast? |
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[This followup was posted to comp.dcom.modems.cable and a copy was sent
to the cited author.]
In article <c_qdnenn1KYx3IjYnZ2dnUVZ_vCdnZ2d@comcast.com>, wcrocker007
@comcast.net says...
| Quote: | Is Comcast assigning everyone static I/P addresses these days? I live in
Macomb, Michigan and I've had the same I/P address for a very long time now.
Powering the cable modem off, and on does not force a change...even if I
leave it off for several hours. Is there a way to force a new I/P address?
|
As other posted, the IP address is roughly based on the MAC address
your computer or router passes on to the modem. Comcast tends to tie an
IP address to a particular modem MAC/computer MAC address for quite
awhile. It typically changes only if you change one of the MAC address,
stay offline for a very long time (I've been off for a few days and
still had the same address), or Comcast makes some structural changes in
their network.
The last time mine changed was a few months ago, when I went through
several address over a few days. This was just before they started there
'PowerBoost' feature.
--
If there is a no_junk in my address, please REMOVE it before replying!
All junk mail senders will be prosecuted to the fullest extent of the
law!!
http://home.att.net/~andyross |
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DLR
Guest
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| Posted: Mon Sep 25, 2006 1:39 am Post subject: Re: Dynamic vs Static I/P with Comcast? |
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Bill Crocker wrote:
| Quote: | Is Comcast assigning everyone static I/P addresses these days? I live in
Macomb, Michigan and I've had the same I/P address for a very long time now.
Powering the cable modem off, and on does not force a change...even if I
leave it off for several hours. Is there a way to force a new I/P address?
In very simple terms. |
Dynamic vs. Static is an arrangement you have with the people upstream
from you.
If it's static it should not change without people getting involved and
coordinating it. I.E. the upstream has committed you'll get the same IP
until they change the deal with you.
If it's dynamic the upstream can change it anytime they want within the
rules of PPPoE, PPPoA, DHCP, or however your connection is made.
Now as a practical mater a static can change and a dynamic not change
give the above. It's up to the upstream.
For a variety of reasons, cable companies seem to not change dynamic IPs
very often, and many ILEC DSL providers seem to change them on a whim. |
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Eric
Guest
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| Posted: Sat Sep 30, 2006 8:11 pm Post subject: Re: Dynamic vs Static I/P with Comcast? |
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Bit Twister wrote:
| Quote: | On Sat, 23 Sep 2006 10:15:55 -0400, Bill Crocker wrote:
Is Comcast assigning everyone static I/P addresses these days?
Yep, not likely to change unless your cable segment gets congested and
they decide to split your segment. You address might change if you
wind up on the new split side.
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And, if you stay on the same CMTS, it is unlikely to change either, due
to interface bundling. Normally, a CMTS (or any router, for that
matter), segments subnets via hard interfaces. However, this tends to
be inefficient and eats up a lot of IP address space or requires a lot
of administration (this happened all the time in the bad old days with
@home. They ALWAYS underestimated subnet requirements and we ran out of
addresses every few weeks). Cisco introdced interface bundling to help
combat this problem, basically turning the CMTS into a switch instead
of a router. Works like a champ, makes everyone happy. Of course if you
are in a major metro area, you will likely see new devices added and
nodes moved to the new device, not a reshuffle. |
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