Technical Cable Modem Q

Discussion in 'The Barracks' started by Fox, Feb 24, 2003.

  1. Derelict

    Derelict Retired Administrator

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    Alternatively Fox, you could have done the path of others and got yourself another firewall.

    Zone Alarm (there's a free edition and a pro edition) by default drops all ICMP Ping packets sent to a machine. So it just makes the appearance that your machine doesn't actually exist as a valid IP.

    ZA is also quite good in protecting against stealthed intruders.

    But that's the reason for having a firewall. Imagine if you don't have a firewall. :shock:

    Or you could get yourself a NAT router. That will instantly remove all traces of people trying to hack into your machine as NAT won't know where to direct the port requests.... that's unless you've got port forward rules in place.
     
  2. SnakeTails

    SnakeTails Well-Known Member

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    But you don't want to drop ALL ICMP packets, certain types are needed for propper communication, dropping them all is the trait of a dumb ass administrator that doesn't know what they are blocking.

    In win2K you could have just dropped to DOS Prompt (easier than reinstalling drivers) and executed the following.

    ipconfig /renew adaptername
     
  3. GnR

    GnR Retired Captain

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    That is an interesting solution. I too had a similar question when I was running a cable modem. I wanted to know if I could change my IP. After a little research I was able to find a solution.

    The way that any network card connected to a DHCP server works is: the DHCP server allocates IP addresses based on the MAC address of the network card. Therefore you can use the renew command to "renew" your IP address all day and never get a new IP address since you have the same MAC address. The only way to get a new IP on demand is to change your MAC address. Unfortunately your MAC address is hard-coded into the chips of your NIC card. Fortunately, Windows allows you to insert a registry key that allows you to essentially change your MAC address in Windows.

    I used this method to change my IP address a number of times on demand. It worked fine on my Windows 98 and Windows 2k machines. I'm not sure if XP or ME would have the same ability to do this.
     
  4. SnakeTails

    SnakeTails Well-Known Member

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    Newer NIC's have the MAC encoded into their E^2ROM so it just needs to be mod'd by the setup software.
     
  5. Warbear.Prime

    Warbear.Prime Well-Known Member

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    Easiest solution with the nic - unplug the cable, move to another pc or nic in same pc, wait 5 seconds, and put back, works best under 2k / xp though.

    It grabs a new IP, and then when you go back it does it again.

    Problem solved no need to reboot or anything...
     
  6. Pseudonym

    Pseudonym Getting Started

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    U r all techno nerds, I have no idea what u r on about.



    Computers = up, down, left ,right, jump, kneel, fire. What more do you need to know?
     
  7. Derelict

    Derelict Retired Administrator

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    You need to know what the actual "0"s and "1"s signals that are used to tell it the "Up/Down/Left/Right/Crouch/Fire"

    Essesntially in summary:

    The cable modem acts like a network card.

    Each network card has a hard wired address name. This address name, the MAC, isn't something that the computer's networking languages can talk at.

    They've standardarised on TCP/IP as the networking language.

    The easiest way to get a unique TCP/IP address is to use DHCP.

    DHCP works down to the lower level of the MAC address in helping assign it's TCP/IP address.

    Trying to release and renew the address you generally then will come back with the same TCP/IP address because of this.

    The removal and readdition of network card drivers from the computer (interface to the cable modem) will have the effects of releasing, then re-enabling the TCP/IP address

    Hmm... no real way to explain this simply.

    Ok Pseudo. Easy EASY EASY method.

    The Computer needs to talk to another computer. It needs to have phone number to use so it can talk. The phone number is assigned by Telstra. :roll:

    You want the phone number changed.

    You go through a long winded process of disconnecting the phone with Telstra, then reconnecting it again with Telstra. Hopefully, you'll come up with a new phone number.

    Does that help? :wink:
     
  8. Pseudonym

    Pseudonym Getting Started

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    I use W,A,S,D for moving and mouse for crouch and fire. It sound awfully complicated to bind 1 and 0 to do all the functions :)


    I say it again u r all nerds. I just used to leave my cable modem unpluged for a few hours and it would grab a new IP when I reconnected.
     
  9. Derelict

    Derelict Retired Administrator

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    Actally Pseudo.

    I believe that the DHCP servers are set up to issue leases of anywhere between 5 to 14 days duration.

    The way the client (your machine) works is it'll ask to renew the lease for the same address at 1/2 the duration length, if it doesn't get a response, it'll ask again at 1/2 again the remaining duration, all the way through until the lease expires - that's when and only when the address is released by the server.

    So if you turned the cable modem off and left it unplugged for a few hours and came back with a new address, you were DAMN lucky.

    Most of the time, you'll have to turn the modem off and disconnected for anywhere up to 2 weeks to get a new address.
     
  10. Pseudonym

    Pseudonym Getting Started

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    What can i say . The gods look after fools and drunks. I will not state which one i am.
     
  11. Arienne

    Arienne The Woman in Red Staff Member Administrator Moderator

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    Can we?

    :lol:
     
  12. Derelict

    Derelict Retired Administrator

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    ROFL

    You evil captain you.
     
  13. Pseudonym

    Pseudonym Getting Started

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  14. Fox

    Fox Clown Administrator Administrator Moderator

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    You mean for Pseudo these two are exclusive :?:
     
  15. Pseudonym

    Pseudonym Getting Started

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    :| :cry: :x :wink: :(
     
  16. Hethrir

    Hethrir Getting Started

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    on optus there is a 24hr lease (ipconfig /all). The range is quite large and so in the time i've had it, my ip addy has been the same. unfortunately some smart ppl look out 4 me online by pinging me till they get a response :evil: then even if i am invisible in trillian they still know 2 message me. time 4 a firewall i think...

    the way i c it, if u r after a static ip addy 4 kicks, not 2 run a server, why bother paying an xtra $10/month or so when u r almost guarenteed 2 get it neway :twisted: ??
     
  17. Father

    Father The Boss Staff Member Administrator Moderator

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    What do you mean, time for a firewall?

    Trust me you should never be on the net without one!
     
  18. Hethrir

    Hethrir Getting Started

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    yeah, but if someone hacks my computer...so what? at the worst i have to re-install windows. but yes you're right :oops:
     
  19. Derelict

    Derelict Retired Administrator

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    Beware of those trojans being fired out from Hethrir's machine as he's browsing these forums Father! :shock: :lol:
     
  20. Hethrir

    Hethrir Getting Started

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    FYI, re-installed XP, and optus gave the same IP address back, so only 98 must get a new IP address on driver re-install...
     

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