zillah Posted March 29, 2005 Share Posted March 29, 2005 I have got at two types of IP addresses which are :1-10.X.X.X we get these IP addresses, if we connect our PCs via wireless card.2-194.X.X.X we get these IP addresses if you connect our PCs wired.As you know that 10.X.X.X private ip addresses (class A), what about IP of format 194.X.X.X (wired) do they consider private IP (within same office) or public IP (not of type class C private address which is 192.168.X.X ) ? Why when I connect my PC wired to same port (same location in room 202) always it have same IP address (say 194.227.160.160), though the IP has been assigned dynamically (not static) ?How can the port itself reserve IP address ? Quote Link to comment Share on other sites More sharing options...
Marsden11 Posted March 29, 2005 Share Posted March 29, 2005 194.x.x.x is publicYou may get the same IP if your DHCP lease is a long duration. Quote Link to comment Share on other sites More sharing options...
zillah Posted March 29, 2005 Author Share Posted March 29, 2005 You may get the same IP if your DHCP lease is a long duration.Could you please give me little bit more details Quote Link to comment Share on other sites More sharing options...
Marsden11 Posted March 29, 2005 Share Posted March 29, 2005 (edited) DHCP uses a lease (predetermined time period) to determine how long your machine keeps its dynamic IP address. If your DHCP server is set to give out long leases say, 30 hours, you went to school every day and connected with your laptop, the DHCP server would continue to hold your MAC Address lease until it timed out. Your MAC address is what identifies your laptop from the millions on the planet. You could plug in and plug out every day and always have the same Dynamic IP address. Edited March 29, 2005 by Marsden11 Quote Link to comment Share on other sites More sharing options...
nlinecomputers Posted March 29, 2005 Share Posted March 29, 2005 To clarify a bit about how that works. DHCP leases can be set for any time period. If your network has them set for say a week then as Marsden states your MAC address is used to make sure that you get the same IP again. Also as part of the process at the halfway point in the lease your computer begins to request a renewal of the lease. So if your lease is set at 7days then at 3.5 days your computer will try and request a new lease for the same number. If you were to not use your computer for longer then the lease time then that number would be freed and you would likely get a new number the next time you connect. Quote Link to comment Share on other sites More sharing options...
Peachy Posted March 29, 2005 Share Posted March 29, 2005 This is called DHCP reservation. Your IT network administrator(s) will have added your laptop's/desktop's MAC address into the DHCP server and assigned it an IP address. So, each time your computer sends a DHCP request packet it will receive the IP address assigned to it. As our ITS manager likes to call it, this is "dynamically assigned static IP addressing!" Quote Link to comment Share on other sites More sharing options...
Stonegiant Posted March 29, 2005 Share Posted March 29, 2005 To clarify a bit about how that works. DHCP leases can be set for any time period. If your network has them set for say a week then as Marsden states your MAC address is used to make sure that you get the same IP again. Also as part of the process at the halfway point in the lease your computer begins to request a renewal of the lease. So if your lease is set at 7days then at 3.5 days your computer will try and request a new lease for the same number. If you were to not use your computer for longer then the lease time then that number would be freed and you would likely get a new number the next time you connect.<{POST_SNAPBACK}> Whoa... Deja vu... I just learned about how leases renew this morning on the way to work from my carpooler. Freaky. Quote Link to comment Share on other sites More sharing options...
zillah Posted March 29, 2005 Author Share Posted March 29, 2005 (edited) Thanks Marsden11 and nlinecomputers and Peachy for this explaination. This is called DHCP reservation. Your IT network administrator(s) will have added your laptop's/desktop's MAC address into the DHCP server and assigned it an IP address1- Could you please (for my knowledge) how will this be done, is there extar featur comes with windows server OSs (2000 or 2003), or Is it third party program.?2- I have got two type of connections at home ADSL and normal dialup.If I tried to ping public address (194.X.X.X ) from normal dial up connection using my laptop I can not ping it!!!!!, I though there is problem with my laptop (winXP).Then I used desktop instead of laptop, (I replaced laptop with desktop) same problem.I changed the connection for laptop from normal dial up to ADSL, I was able to ping the same public address (194.X.X.X ). Why does this happen ? Edited March 29, 2005 by zillah Quote Link to comment Share on other sites More sharing options...
mispunt Posted March 30, 2005 Share Posted March 30, 2005 1- Could you please (for my knowledge) how will this be done, is there extar featur comes with windows server OSs (2000 or 2003), or Is it third party program.?This could be done on every dhcp server, but personaly I doubt it if this is done for your mac address...2- I have got two type of connections at home ADSL and normal dialup.If I tried to ping public address (194.X.X.X ) from normal dial up connection using my laptop I can not ping it!!!!!, I though there is problem with my laptop (winXP).Then I used desktop instead of laptop, (I replaced laptop with desktop) same problem.I changed the connection for laptop from normal dial up to ADSL, I was able to ping the same public address (194.X.X.X ). Why does this happen ?<{POST_SNAPBACK}> For as far as I could see is that the two ip addresses are from your work/school. This could mean that you've got another IP address at home... (so you could not reach that public address. Quote Link to comment Share on other sites More sharing options...
zillah Posted March 31, 2005 Author Share Posted March 31, 2005 This could mean that you've got another IP address at home... (so you could not reach that public address.I did not get what did you mean? Quote Link to comment Share on other sites More sharing options...
mispunt Posted March 31, 2005 Share Posted March 31, 2005 Those IP address, from where are they? from your home or from your work/school?If they are from your work (and you've got another IP address at home) you probably can't ping the network you want to reach... Quote Link to comment Share on other sites More sharing options...
Marsden11 Posted March 31, 2005 Share Posted March 31, 2005 You should be able to ping any public IP not behind a firewall from work or home. Quote Link to comment Share on other sites More sharing options...
zillah Posted March 31, 2005 Author Share Posted March 31, 2005 (edited) Those IP address, from where are they?Those IPs are at work, and I am trying to ping them from home.Format of IPs at home:1- ADSL Connection 217.X.X.X2- Normal Dialup connection 213.X.X.X Edited March 31, 2005 by zillah Quote Link to comment Share on other sites More sharing options...
zillah Posted March 31, 2005 Author Share Posted March 31, 2005 Marsden11 194.x.x.x is publicWhat will the case be, if this IP is used within LAN of university or school or work. Is it translated by using NAT ? If so, does it still consider as public address ? because as you know public address can exist on net (correct me if I am wrong) Quote Link to comment Share on other sites More sharing options...
mispunt Posted March 31, 2005 Share Posted March 31, 2005 Is it translated by using NAT ? If so, does it still consider as public address ? because as you know public address can exist on net (correct me if I am wrong)<{POST_SNAPBACK}> It is possible that the addresses are translated with NAT, and yes it is still a public address.When it is translated with NAT than you could not reach it (I think)Another possibility is that the router/firewall is blocking the ping.You could do a trace (go to the dos box and type "tracert <ip>") you will see how far you can get. Quote Link to comment Share on other sites More sharing options...
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