RE: Subnet question [7:60711]
OR , you don't have to change the IP , you can simply change the Vlan on the port to work for the IP on the WKST. As long as you have DHCP up and running and you have got vlans configured on your switch , you can move a pc any where , put the port into the correct Vlan , and you will work. I have set up a four story building with 2000 P.C's , haven't had a day's problem :) -Original Message- From: MADMAN [mailto:[EMAIL PROTECTED]] Sent: Thursday, January 09, 2003 7:25 PM To: [EMAIL PROTECTED] Subject: Re: Subnet question [7:60711] don't do anything. If you put a 10.100.1.x host on the 10.100.2.x network it won't work until you do change the IP. Dave Tamhankar, Nitin wrote: This might be a very elementary question for some of you guys but I would appreciate the answer. If an office which has 3 different floors and has Cisco routers and catalyst switches and windows environment. We need to configure it in such a way that each floor is on its own subnet for example floor1 100.10.1.0 floor2 100.10.2.0 floor3 100.10.3.0 Also if a computer which has IP address in subnet 100.10.1.0 is moved from floor 1 to floor 2, it should not communicate with the network unless its IP address is changed to one in 100.10.2.0 subnet. How it can be accomplished? Thank you Nitin [GroupStudy.com removed an attachment of type application/ms-tnef] -- David Madland CCIE# 2016 Sr. Network Engineer Qwest Communications 612-664-3367 You don't make the poor richer by making the rich poorer. --Winston Churchill NOTICE - This message contains privileged and confidential information intended only for the use of the addressee named above. Any review, retransmission, dissemination, copying, disclosure or other use of, or taking of any action in reliance upon, this information by person or entities other than the intended recipient is prohibited. If you have received this message in error, please notify the sender by return email and delete this message. This message should not be copied or used for any purpose other than intended, nor should it be disclosed to any other person. Any views expressed in this message are those of the individual sender, except where the sender specifically states them to be the view of Investec Group, its subsidiaries or associates. The Investec Group is not liable for the security of information sent by e-mail at your request, nor for the proper and complete transmission of the information contained in the communication nor for any delay in its receipt. Please note that the recipient must scan this e-mail and any attached files for viruses and the like. The Investec Group accepts no liability of whatever nature for any loss, liability, damage or expense resulting directly or indirectly from the access of any files which are attached to this message. Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=60797t=60711 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Subnet question [7:60711]
I would set up VLAN's keep in mind you need to route between VLAN's. This is done via RSM or router on a stick. -Original Message- From: Tamhankar, Nitin [mailto:[EMAIL PROTECTED]] Sent: Thursday, January 09, 2003 11:40 AM To: [EMAIL PROTECTED] Subject: Subnet question [7:60711] This might be a very elementary question for some of you guys but I would appreciate the answer. If an office which has 3 different floors and has Cisco routers and catalyst switches and windows environment. We need to configure it in such a way that each floor is on its own subnet for example floor1 100.10.1.0 floor2 100.10.2.0 floor3 100.10.3.0 Also if a computer which has IP address in subnet 100.10.1.0 is moved from floor 1 to floor 2, it should not communicate with the network unless its IP address is changed to one in 100.10.2.0 subnet. How it can be accomplished? Thank you Nitin [GroupStudy.com removed an attachment of type application/ms-tnef] Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=60821t=60711 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Subnet question [7:60711]
I would set up VLAN's keep in mind you need to route between VLAN's. This is done via RSM or router on a stick. Daniel Ladrach CCNA, CCNP WorldCom Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=60836t=60711 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Subnet question [7:60711]
Don't forget the Simplicity Principle! :-) I liked MADMAN's answer best. He's a CCIE and it shows. Without some idea of the fellow's topology, we can't recommend VLANs, and, although I know VLANs are extremely popular and the obvious choice for some situations, they add complexity that may not be necessary. And recommending Mobile IP for something as simple as this is definitely overkill. Priscilla Xia Hongbing wrote: One thing I want to mentioned is that Mobile IP can solve your problem. You can move to another place without changing your IP address, but still keep connection. However, you must configure both floor 1 and floor 2 router to support Foreign agent and home agent function. Your computer client also support mobile IP registration. - Original Message - From: Priscilla Oppenheimer To: Sent: Thursday, January 09, 2003 4:58 PM Subject: RE: Subnet question [7:60711] Larry Letterman wrote: thats pris's job hereif she writes enough detailed answers we dont have to buy her books...:) Oh no! By the way, the only nicknames that are supported are Cilla, PO, (and Cil, if you are Chuck.) Nicknames that map to sissified have been deprecated. The preferred name is my canonical name, Priscilla. :-) Larry Letterman Network Engineer San Jose Transport Cisco Systems Inc. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Tamhankar, Nitin Sent: Thursday, January 09, 2003 11:18 AM To: [EMAIL PROTECTED] Subject: RE: Subnet question [7:60711] Thank you very much for taking pains to right such a detailed explanation. Thank you all for your answers they were very helpful. Thanks Nitin -Original Message- From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]] Sent: Thursday, January 09, 2003 12:36 PM To: [EMAIL PROTECTED] Subject: RE: Subnet question [7:60711] You may not need virtual LANs. Real LANs solve the problem. :-) This is a classic case of subnetting. With DHCP, the client should get the right address when it broadcasts after it moves, so there's no issue. Leaving DHCP out of the picture, the need to ensure that a moved node can't communicate is met simply by the way IP works. Assume there's a client with this config: address = 100.10.1.100 subnet mask = 255.255.255.0 default gateway = 100.10.1.1 Assume the client is physically sitting on the 100.10.2.0/24 network. When it wants to send to nodes on the 100.10.1.0 network, it will compare its address with the destination address, assume it's on the same subnet, and send an ARP broadcast. The ARP broadcast won't reach the destination though, which is on a different LAN, so it won't work. (Make sure the router isn't configured for Proxy ARP. But even with Proxy ARP, communication won't work. With Proxy ARP, the router could respond on behalf of the destination on the 100.10.1.0 network. However that host wouldn't be able to respond because it would assume that 100.10.1.1 is local.) Assume the client wishes to reach devices on the 100.10.2.0 or 100.10.3.0 network. It will compare its address with the destination address and decide that it's not on the same subnet, so it needs to send to the default gateway. It will send a broadcast for the default gateway, which won't work because 10.10.1.1 is on a different LAN. Once again make sure Proxy ARP is disabled. I'll leave it to the reader to figure out what would happen in this case if Proxy ARP were enabled. :-) The question of VLANs versus real LANs requires more info. How many router ports to you have? Is each router port a subnet? Or do you plan to have multiple subnets out one router port, in which case you need VLANs and inter-VLAN routing on the router. ___ Priscilla Oppenheimer www.troubleshootingnetworks.com www.priscilla.com Nathan Nakao wrote: I'd probably use VLAN's. Conf t Int vlan 101 Int vlan 102 Int vlan 103 Then setup the DHCP to assign IP addresses accordingly. Once that is done. Set the vlans to 101 for first floor, 102 for second floor, and 103 for third floor. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Tamhankar, Nitin Sent: Thursday, January 09, 2003 8:40 AM To: [EMAIL PROTECTED] Subject: Subnet question [7:60711] This might be a very elementary question for some of you guys but I would appreciate the answer. If an office which has 3 different floors and has Cisco routers
RE: Subnet question [7:60711]
I'd probably use VLAN's. Conf t Int vlan 101 Int vlan 102 Int vlan 103 Then setup the DHCP to assign IP addresses accordingly. Once that is done. Set the vlans to 101 for first floor, 102 for second floor, and 103 for third floor. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Tamhankar, Nitin Sent: Thursday, January 09, 2003 8:40 AM To: [EMAIL PROTECTED] Subject: Subnet question [7:60711] This might be a very elementary question for some of you guys but I would appreciate the answer. If an office which has 3 different floors and has Cisco routers and catalyst switches and windows environment. We need to configure it in such a way that each floor is on its own subnet for example floor1 100.10.1.0 floor2 100.10.2.0 floor3 100.10.3.0 Also if a computer which has IP address in subnet 100.10.1.0 is moved from floor 1 to floor 2, it should not communicate with the network unless its IP address is changed to one in 100.10.2.0 subnet. How it can be accomplished? Thank you Nitin [GroupStudy.com removed an attachment of type application/ms-tnef] Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=60716t=60711 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Subnet question [7:60711]
don't do anything. If you put a 10.100.1.x host on the 10.100.2.x network it won't work until you do change the IP. Dave Tamhankar, Nitin wrote: This might be a very elementary question for some of you guys but I would appreciate the answer. If an office which has 3 different floors and has Cisco routers and catalyst switches and windows environment. We need to configure it in such a way that each floor is on its own subnet for example floor1 100.10.1.0 floor2 100.10.2.0 floor3 100.10.3.0 Also if a computer which has IP address in subnet 100.10.1.0 is moved from floor 1 to floor 2, it should not communicate with the network unless its IP address is changed to one in 100.10.2.0 subnet. How it can be accomplished? Thank you Nitin [GroupStudy.com removed an attachment of type application/ms-tnef] -- David Madland CCIE# 2016 Sr. Network Engineer Qwest Communications 612-664-3367 You don't make the poor richer by making the rich poorer. --Winston Churchill Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=60717t=60711 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Subnet question [7:60711]
You may not need virtual LANs. Real LANs solve the problem. :-) This is a classic case of subnetting. With DHCP, the client should get the right address when it broadcasts after it moves, so there's no issue. Leaving DHCP out of the picture, the need to ensure that a moved node can't communicate is met simply by the way IP works. Assume there's a client with this config: address = 100.10.1.100 subnet mask = 255.255.255.0 default gateway = 100.10.1.1 Assume the client is physically sitting on the 100.10.2.0/24 network. When it wants to send to nodes on the 100.10.1.0 network, it will compare its address with the destination address, assume it's on the same subnet, and send an ARP broadcast. The ARP broadcast won't reach the destination though, which is on a different LAN, so it won't work. (Make sure the router isn't configured for Proxy ARP. But even with Proxy ARP, communication won't work. With Proxy ARP, the router could respond on behalf of the destination on the 100.10.1.0 network. However that host wouldn't be able to respond because it would assume that 100.10.1.1 is local.) Assume the client wishes to reach devices on the 100.10.2.0 or 100.10.3.0 network. It will compare its address with the destination address and decide that it's not on the same subnet, so it needs to send to the default gateway. It will send a broadcast for the default gateway, which won't work because 10.10.1.1 is on a different LAN. Once again make sure Proxy ARP is disabled. I'll leave it to the reader to figure out what would happen in this case if Proxy ARP were enabled. :-) The question of VLANs versus real LANs requires more info. How many router ports to you have? Is each router port a subnet? Or do you plan to have multiple subnets out one router port, in which case you need VLANs and inter-VLAN routing on the router. ___ Priscilla Oppenheimer www.troubleshootingnetworks.com www.priscilla.com Nathan Nakao wrote: I'd probably use VLAN's. Conf t Int vlan 101 Int vlan 102 Int vlan 103 Then setup the DHCP to assign IP addresses accordingly. Once that is done. Set the vlans to 101 for first floor, 102 for second floor, and 103 for third floor. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Tamhankar, Nitin Sent: Thursday, January 09, 2003 8:40 AM To: [EMAIL PROTECTED] Subject: Subnet question [7:60711] This might be a very elementary question for some of you guys but I would appreciate the answer. If an office which has 3 different floors and has Cisco routers and catalyst switches and windows environment. We need to configure it in such a way that each floor is on its own subnet for example floor1 100.10.1.0 floor2 100.10.2.0 floor3 100.10.3.0 Also if a computer which has IP address in subnet 100.10.1.0 is moved from floor 1 to floor 2, it should not communicate with the network unless its IP address is changed to one in 100.10.2.0 subnet. How it can be accomplished? Thank you Nitin [GroupStudy.com removed an attachment of type application/ms-tnef] Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=60724t=60711 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Subnet question [7:60711]
Thank you very much for taking pains to right such a detailed explanation. Thank you all for your answers they were very helpful. Thanks Nitin -Original Message- From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]] Sent: Thursday, January 09, 2003 12:36 PM To: [EMAIL PROTECTED] Subject: RE: Subnet question [7:60711] You may not need virtual LANs. Real LANs solve the problem. :-) This is a classic case of subnetting. With DHCP, the client should get the right address when it broadcasts after it moves, so there's no issue. Leaving DHCP out of the picture, the need to ensure that a moved node can't communicate is met simply by the way IP works. Assume there's a client with this config: address = 100.10.1.100 subnet mask = 255.255.255.0 default gateway = 100.10.1.1 Assume the client is physically sitting on the 100.10.2.0/24 network. When it wants to send to nodes on the 100.10.1.0 network, it will compare its address with the destination address, assume it's on the same subnet, and send an ARP broadcast. The ARP broadcast won't reach the destination though, which is on a different LAN, so it won't work. (Make sure the router isn't configured for Proxy ARP. But even with Proxy ARP, communication won't work. With Proxy ARP, the router could respond on behalf of the destination on the 100.10.1.0 network. However that host wouldn't be able to respond because it would assume that 100.10.1.1 is local.) Assume the client wishes to reach devices on the 100.10.2.0 or 100.10.3.0 network. It will compare its address with the destination address and decide that it's not on the same subnet, so it needs to send to the default gateway. It will send a broadcast for the default gateway, which won't work because 10.10.1.1 is on a different LAN. Once again make sure Proxy ARP is disabled. I'll leave it to the reader to figure out what would happen in this case if Proxy ARP were enabled. :-) The question of VLANs versus real LANs requires more info. How many router ports to you have? Is each router port a subnet? Or do you plan to have multiple subnets out one router port, in which case you need VLANs and inter-VLAN routing on the router. ___ Priscilla Oppenheimer www.troubleshootingnetworks.com www.priscilla.com Nathan Nakao wrote: I'd probably use VLAN's. Conf t Int vlan 101 Int vlan 102 Int vlan 103 Then setup the DHCP to assign IP addresses accordingly. Once that is done. Set the vlans to 101 for first floor, 102 for second floor, and 103 for third floor. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Tamhankar, Nitin Sent: Thursday, January 09, 2003 8:40 AM To: [EMAIL PROTECTED] Subject: Subnet question [7:60711] This might be a very elementary question for some of you guys but I would appreciate the answer. If an office which has 3 different floors and has Cisco routers and catalyst switches and windows environment. We need to configure it in such a way that each floor is on its own subnet for example floor1 100.10.1.0 floor2 100.10.2.0 floor3 100.10.3.0 Also if a computer which has IP address in subnet 100.10.1.0 is moved from floor 1 to floor 2, it should not communicate with the network unless its IP address is changed to one in 100.10.2.0 subnet. How it can be accomplished? Thank you Nitin [GroupStudy.com removed an attachment of type application/ms-tnef] Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=60728t=60711 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Subnet question [7:60711]
Surely there are a lot of solutions; which I'd do is: Define a different VLAN for each floor. Connect the catalysts in each floor with trunk interfaces (802.1q) Connect a Fast or Giga ethernet interface from a router to one of the switches. You must setup that interface (both on the router an on the switch side) as DOT1Q. On the router you can do it with the following config: -- Note: VLAN 101 - Floor 1 VLAN 102 - Floor 2 VLAN 103 - Floor 3 interface fastethernet 0/0 (for example) full-duplex (Duplex full?) speed 100 no ip address interface fastethernet 0/0.101 encap dot1q 101 ip address 10.100.1.254 255.255.255.0 interface fastethernet 0/0.102 encap dot1q 102 ip address 10.100.2.254 255.255.255.0 interface fastethernet 0/0.103 encap dot1q 103 ip address 10.100.3.254 255.255.255.0 If you tell us which switches are you using (cat or IOS based) I can put you a config for that; assuming they are IOS, it is more or less: --- Switch on floor 1: interface FastEthernet0/1 switchport access vlan 101 switchport mode access duplex full speed 100 interface FastEthernet0/2 switchport access vlan 101 switchport mode access duplex full speed 100 ... ! Trunk to floor 2 interface FastEthernet0/10 switchport mode trunk duplex full speed 100 .. Switch on floor 2: interface FastEthernet0/1 switchport access vlan 102 switchport mode access duplex full speed 100 interface FastEthernet0/2 switchport access vlan 102 switchport mode access duplex full speed 100 ... ! Trunk to floor 1 interface FastEthernet0/10 switchport mode trunk duplex full speed 100 ! Trunk to floor 3 interface FastEthernet0/11 switchport mode trunk duplex full speed 100 Francisco Sedano Informatica Pronet CCIE Student :-) Tamhankar, Nitin Enviado por: [EMAIL PROTECTED] 09/01/2003 17:40 Por favor, responda a Tamhankar, Nitin Para: [EMAIL PROTECTED] cc: Asunto: Subnet question [7:60711] This might be a very elementary question for some of you guys but I would appreciate the answer. If an office which has 3 different floors and has Cisco routers and catalyst switches and windows environment. We need to configure it in such a way that each floor is on its own subnet for example floor1 100.10.1.0 floor2 100.10.2.0 floor3 100.10.3.0 Also if a computer which has IP address in subnet 100.10.1.0 is moved from floor 1 to floor 2, it should not communicate with the network unless its IP address is changed to one in 100.10.2.0 subnet. How it can be accomplished? Thank you Nitin [GroupStudy.com removed an attachment of type application/ms-tnef] Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=60754t=60711 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Subnet question [7:60711]
Larry Letterman wrote: thats pris's job hereif she writes enough detailed answers we dont have to buy her books...:) Oh no! By the way, the only nicknames that are supported are Cilla, PO, (and Cil, if you are Chuck.) Nicknames that map to sissified have been deprecated. The preferred name is my canonical name, Priscilla. :-) Larry Letterman Network Engineer San Jose Transport Cisco Systems Inc. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Tamhankar, Nitin Sent: Thursday, January 09, 2003 11:18 AM To: [EMAIL PROTECTED] Subject: RE: Subnet question [7:60711] Thank you very much for taking pains to right such a detailed explanation. Thank you all for your answers they were very helpful. Thanks Nitin -Original Message- From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]] Sent: Thursday, January 09, 2003 12:36 PM To: [EMAIL PROTECTED] Subject: RE: Subnet question [7:60711] You may not need virtual LANs. Real LANs solve the problem. :-) This is a classic case of subnetting. With DHCP, the client should get the right address when it broadcasts after it moves, so there's no issue. Leaving DHCP out of the picture, the need to ensure that a moved node can't communicate is met simply by the way IP works. Assume there's a client with this config: address = 100.10.1.100 subnet mask = 255.255.255.0 default gateway = 100.10.1.1 Assume the client is physically sitting on the 100.10.2.0/24 network. When it wants to send to nodes on the 100.10.1.0 network, it will compare its address with the destination address, assume it's on the same subnet, and send an ARP broadcast. The ARP broadcast won't reach the destination though, which is on a different LAN, so it won't work. (Make sure the router isn't configured for Proxy ARP. But even with Proxy ARP, communication won't work. With Proxy ARP, the router could respond on behalf of the destination on the 100.10.1.0 network. However that host wouldn't be able to respond because it would assume that 100.10.1.1 is local.) Assume the client wishes to reach devices on the 100.10.2.0 or 100.10.3.0 network. It will compare its address with the destination address and decide that it's not on the same subnet, so it needs to send to the default gateway. It will send a broadcast for the default gateway, which won't work because 10.10.1.1 is on a different LAN. Once again make sure Proxy ARP is disabled. I'll leave it to the reader to figure out what would happen in this case if Proxy ARP were enabled. :-) The question of VLANs versus real LANs requires more info. How many router ports to you have? Is each router port a subnet? Or do you plan to have multiple subnets out one router port, in which case you need VLANs and inter-VLAN routing on the router. ___ Priscilla Oppenheimer www.troubleshootingnetworks.com www.priscilla.com Nathan Nakao wrote: I'd probably use VLAN's. Conf t Int vlan 101 Int vlan 102 Int vlan 103 Then setup the DHCP to assign IP addresses accordingly. Once that is done. Set the vlans to 101 for first floor, 102 for second floor, and 103 for third floor. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Tamhankar, Nitin Sent: Thursday, January 09, 2003 8:40 AM To: [EMAIL PROTECTED] Subject: Subnet question [7:60711] This might be a very elementary question for some of you guys but I would appreciate the answer. If an office which has 3 different floors and has Cisco routers and catalyst switches and windows environment. We need to configure it in such a way that each floor is on its own subnet for example floor1 100.10.1.0 floor2 100.10.2.0 floor3 100.10.3.0 Also if a computer which has IP address in subnet 100.10.1.0 is moved from floor 1 to floor 2, it should not communicate with the network unless its IP address is changed to one in 100.10.2.0 subnet. How it can be accomplished? Thank you Nitin [GroupStudy.com removed an attachment of type application/ms-tnef] Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=60774t=60711 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Subnet question [7:60711]
I'll open a TAC case to have other names supported... Larry Letterman Network Engineer San Jose Transport Cisco Systems Inc. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: Thursday, January 09, 2003 4:58 PM To: [EMAIL PROTECTED] Subject: RE: Subnet question [7:60711] Larry Letterman wrote: thats pris's job hereif she writes enough detailed answers we dont have to buy her books...:) Oh no! By the way, the only nicknames that are supported are Cilla, PO, (and Cil, if you are Chuck.) Nicknames that map to sissified have been deprecated. The preferred name is my canonical name, Priscilla. :-) Larry Letterman Network Engineer San Jose Transport Cisco Systems Inc. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Tamhankar, Nitin Sent: Thursday, January 09, 2003 11:18 AM To: [EMAIL PROTECTED] Subject: RE: Subnet question [7:60711] Thank you very much for taking pains to right such a detailed explanation. Thank you all for your answers they were very helpful. Thanks Nitin -Original Message- From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]] Sent: Thursday, January 09, 2003 12:36 PM To: [EMAIL PROTECTED] Subject: RE: Subnet question [7:60711] You may not need virtual LANs. Real LANs solve the problem. :-) This is a classic case of subnetting. With DHCP, the client should get the right address when it broadcasts after it moves, so there's no issue. Leaving DHCP out of the picture, the need to ensure that a moved node can't communicate is met simply by the way IP works. Assume there's a client with this config: address = 100.10.1.100 subnet mask = 255.255.255.0 default gateway = 100.10.1.1 Assume the client is physically sitting on the 100.10.2.0/24 network. When it wants to send to nodes on the 100.10.1.0 network, it will compare its address with the destination address, assume it's on the same subnet, and send an ARP broadcast. The ARP broadcast won't reach the destination though, which is on a different LAN, so it won't work. (Make sure the router isn't configured for Proxy ARP. But even with Proxy ARP, communication won't work. With Proxy ARP, the router could respond on behalf of the destination on the 100.10.1.0 network. However that host wouldn't be able to respond because it would assume that 100.10.1.1 is local.) Assume the client wishes to reach devices on the 100.10.2.0 or 100.10.3.0 network. It will compare its address with the destination address and decide that it's not on the same subnet, so it needs to send to the default gateway. It will send a broadcast for the default gateway, which won't work because 10.10.1.1 is on a different LAN. Once again make sure Proxy ARP is disabled. I'll leave it to the reader to figure out what would happen in this case if Proxy ARP were enabled. :-) The question of VLANs versus real LANs requires more info. How many router ports to you have? Is each router port a subnet? Or do you plan to have multiple subnets out one router port, in which case you need VLANs and inter-VLAN routing on the router. ___ Priscilla Oppenheimer www.troubleshootingnetworks.com www.priscilla.com Nathan Nakao wrote: I'd probably use VLAN's. Conf t Int vlan 101 Int vlan 102 Int vlan 103 Then setup the DHCP to assign IP addresses accordingly. Once that is done. Set the vlans to 101 for first floor, 102 for second floor, and 103 for third floor. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Tamhankar, Nitin Sent: Thursday, January 09, 2003 8:40 AM To: [EMAIL PROTECTED] Subject: Subnet question [7:60711] This might be a very elementary question for some of you guys but I would appreciate the answer. If an office which has 3 different floors and has Cisco routers and catalyst switches and windows environment. We need to configure it in such a way that each floor is on its own subnet for example floor1 100.10.1.0 floor2 100.10.2.0 floor3 100.10.3.0 Also if a computer which has IP address in subnet 100.10.1.0 is moved from floor 1 to floor 2, it should not communicate with the network unless its IP address is changed to one in 100.10.2.0 subnet. How it can be accomplished? Thank you Nitin [GroupStudy.com removed an attachment of type application/ms-tnef] Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=60781t=60711 -- FAQ, list archives, and subscription info
Re: Subnet question [7:60711]
One thing I want to mentioned is that Mobile IP can solve your problem. You can move to another place without changing your IP address, but still keep connection. However, you must configure both floor 1 and floor 2 router to support Foreign agent and home agent function. Your computer client also support mobile IP registration. - Original Message - From: Priscilla Oppenheimer To: Sent: Thursday, January 09, 2003 4:58 PM Subject: RE: Subnet question [7:60711] Larry Letterman wrote: thats pris's job hereif she writes enough detailed answers we dont have to buy her books...:) Oh no! By the way, the only nicknames that are supported are Cilla, PO, (and Cil, if you are Chuck.) Nicknames that map to sissified have been deprecated. The preferred name is my canonical name, Priscilla. :-) Larry Letterman Network Engineer San Jose Transport Cisco Systems Inc. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Tamhankar, Nitin Sent: Thursday, January 09, 2003 11:18 AM To: [EMAIL PROTECTED] Subject: RE: Subnet question [7:60711] Thank you very much for taking pains to right such a detailed explanation. Thank you all for your answers they were very helpful. Thanks Nitin -Original Message- From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]] Sent: Thursday, January 09, 2003 12:36 PM To: [EMAIL PROTECTED] Subject: RE: Subnet question [7:60711] You may not need virtual LANs. Real LANs solve the problem. :-) This is a classic case of subnetting. With DHCP, the client should get the right address when it broadcasts after it moves, so there's no issue. Leaving DHCP out of the picture, the need to ensure that a moved node can't communicate is met simply by the way IP works. Assume there's a client with this config: address = 100.10.1.100 subnet mask = 255.255.255.0 default gateway = 100.10.1.1 Assume the client is physically sitting on the 100.10.2.0/24 network. When it wants to send to nodes on the 100.10.1.0 network, it will compare its address with the destination address, assume it's on the same subnet, and send an ARP broadcast. The ARP broadcast won't reach the destination though, which is on a different LAN, so it won't work. (Make sure the router isn't configured for Proxy ARP. But even with Proxy ARP, communication won't work. With Proxy ARP, the router could respond on behalf of the destination on the 100.10.1.0 network. However that host wouldn't be able to respond because it would assume that 100.10.1.1 is local.) Assume the client wishes to reach devices on the 100.10.2.0 or 100.10.3.0 network. It will compare its address with the destination address and decide that it's not on the same subnet, so it needs to send to the default gateway. It will send a broadcast for the default gateway, which won't work because 10.10.1.1 is on a different LAN. Once again make sure Proxy ARP is disabled. I'll leave it to the reader to figure out what would happen in this case if Proxy ARP were enabled. :-) The question of VLANs versus real LANs requires more info. How many router ports to you have? Is each router port a subnet? Or do you plan to have multiple subnets out one router port, in which case you need VLANs and inter-VLAN routing on the router. ___ Priscilla Oppenheimer www.troubleshootingnetworks.com www.priscilla.com Nathan Nakao wrote: I'd probably use VLAN's. Conf t Int vlan 101 Int vlan 102 Int vlan 103 Then setup the DHCP to assign IP addresses accordingly. Once that is done. Set the vlans to 101 for first floor, 102 for second floor, and 103 for third floor. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Tamhankar, Nitin Sent: Thursday, January 09, 2003 8:40 AM To: [EMAIL PROTECTED] Subject: Subnet question [7:60711] This might be a very elementary question for some of you guys but I would appreciate the answer. If an office which has 3 different floors and has Cisco routers and catalyst switches and windows environment. We need to configure it in such a way that each floor is on its own subnet for example floor1 100.10.1.0 floor2 100.10.2.0 floor3 100.10.3.0 Also if a computer which has IP address in subnet 100.10.1.0 is moved from floor 1 to floor 2, it should not communicate with the network unless its IP address is changed to one in 100.10.2.0 subnet. How it can be accomplished? Thank you Nitin [GroupStudy.com removed an attachment of type application/ms-tnef] Message
