US Cable Support > Mediacom > can't change supposedly dynamic IP address

can't change supposedly dynamic IP address

First, there are two networks running DHCP: your internal network (the LAN with your PC's etc) which has nothing to do with your external network (the Internet for which you get a public IP address).

Your router is running DHCP on your LAN for each PC. Using ipconfig /release on a PC will not do anything for your external / public IP address which is managed by your ISP.

Without knowing which ISP you're using it's hard to provide specific advice.

One thing to try: Turn off your modem/router over night in the hopes that the DCHP renew time have expired and when you next power on the modem you will get a new IP address. This won't work, however, if your ISP is doing MAC binding with your modem/router.

P.S. why are you sending mail directly from your computer -- should it either be going through your ISP or through a service such as Yahoo, Gmail, etc?
--
♬ Music is life ♬

The ISP is Mediacom. I turned off the modem, router, & PC last night & left it off for over 16 hours. Unforunately, that didn't help. If the ISP is doing MAC binding, how do you suggest getting around that?

Also, when I send email from my PC, it goes through my ISP. That's when Spamcop blocks the IP address which seems to be static even though DHCP is enabled. But, when I send an email from my phone, using the same POP outgoing server but a completely different IP address, Spamcop does not block the email.

reply to Ellen098
Moved in from Software for further assistance...

reply to Ellen098

reply to Ellen098
Mediacom associates MAC address to IP in the DHCP lease. The reason your PC will get a different IP than your router because they are different MAC addresses. If you spoof a new MAC address on your router, you'll get a different IP.

How can I spoof the MAC address? I see the option of "Clone your MAC IP" from one of my router's menus but what's the advantage of cloning it if the ISP is already reading it & basing the IP address on it? Thanks for your answer.

Basically, if you clone your MAC it makes the router show Mediacom a different MAC address so then you will get a new IP.

I've already tried cloning the address & it didn't change afterwards. In any case, isn't that really the opposite of spoofing?

I found instructions to spoof from IronGeek.com. I don't have a problem with editing the registry as I just back it up beforehand, but do these instructions look valid to anyone here who know how to spoof Mac addresses?

In XP you can use the regedit to edit the registry from a GUI or the reg command to edit it from the console, I'll be using regedit. Information on all your NICs can be found the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\ Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\ . Under this key you will find a bunch of sub keys labeled as 0000, 00001, 0002 and so forth. We can assume any MAC address we want by finding the key that controls the NIC we want to change, putting in a string value called "NetworkAddress" and setting it to the MAC address we want to use formatted as a twelve digit hex number (example: 000000000001). To find out which key is which we can search through them for the value "DriverDesc" until we find the one that matches the NIC we wish to alter. After you set "NetworkAddress" to the address you want just restart the NIC by disabling it then enabling it (or in the case of PCMCIA cards, just eject and reinsert). You can confirm the MAC address change by using the "getmac" or "ipconfig /all" commands.

TIA.

It needs to be done on the router, not your computer.

reply to ZC_217

Are you saying it's the modem's MAC which the IP is derived from? If so, why would the IP address have changed when I didn't use the router?

In any case, is there any way for me to change the IP address without the assistance of Mediacom? If not, since it's defective for all practical purposes (i.e. I have to keep sending emails to myself, downloading them on my phone, & then forwarding them to the intended recipients), how likely do you think it is that Mediacom will do something to change my IP address, which Spamcop has put on a spam list?

reply to CappinHoff
I actually had success with getting a new IP once the device (or MAC) that is connected to the modem changed. If this doesn't work you can contact MediacomChad and he can help you.
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I speak for myself, not my employer.

reply to Ellen098
Usually when you change the MAC address that is connected to the LAN side of the Modem, you will receive a new IP address. So in the router, you would clone the MAC from one of your computers on the network, then recycle the modem, you should then get a new external IP address.

reply to Ellen098

Norman,

Yes, I mean spamcop.net, I'm not running a mail server, & I use POP email with mail.mchsi.com as the outgoing server when using my PC.

If so, your IP address is not the problem, the Mediacom mail submission host IP address is the problem; and changing your IP address will fix nothing.

I'm glad you mentioned that. I checked the notice again & was surprised by what I saw. I've replaced the actual email address, my IP address, & another IP address below:

Reporting-MTA: dns; dsmdc-mail-omta-03 [10.4.20.34]
Received-From-MTA: dns; [127.0.0.1] [my IP address]
Arrival-Date: Tue, 16 Oct 2012 13:59:04 -0500

Final-recipient: rfc822; [email address]
Action: failed
Status: 5.1.1
Diagnostic-Code: smtp; 550 Unable to add [email address] because host=
[different IP address] is listed on RBL bl.spamcop.net
Last-attempt-Date: Tue, 16 Oct 2012 13:59:05 -0500

Is your "Final-recipient" email address for another Mediacom user?

Interesting. Looking up the MX record for 'mchsi.com' gives me a host name. When I attempt to connect, I get:

C:\Dig>telnet smtp.mchsi.com 25
Connecting To smtp.mchsi.com...
220 dsmdc-mail-imta-02 bizsmtp ESMTP server ready
quit
221 2.0.0 dsmdc-mail-imta-02 bizsmtp closing connection
 
Connection to host lost.
 

Very interesting. If that's true, I wonder if lots of other people are running into this problem too. I'll try smtp.mchsi.com next to see if that helps. Hopefully a server won't block itself. If it doesn't help, I'll try mediacombb.net, which I had to use for awhile last year after an "upgrade". Do you know if mediacombb.net uses the same IP as mchsi.com?

Also, the final user is not a Mediacom subscriber.

BTW, how do you find out an MX record? Thanks very much for checking this out.