Weird DHCP/VLAN solution suggestions wanted!! [7:6579]
Hello everyone, Just wondering if anyone out there has come across this same issue: I am currently working on a site where each office in the building (29 offices) will be connected to a pair of 2924XL switches, and each office will also be in its own vlan (and therefore have its own network, routed between at the router). The problem is the client wants to use DHCP, so that people in the offices can simply plug in and away they go. But how would you go about implementing a DHCP server in this situation?? In order to allocate an address from the appropriate range, the DHCP server needs to be aware of the VLAN that the client DHCP request came from. I have not been able to find a DHCP server that has this capability whatsoever. I am sure this has been done before - does anyone know how or have any suggestions?? Any help much appreciated! Please copy my email address in on the reply as well as to the group. Thanks! Sam. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=6579&t=6579 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Weird DHCP/VLAN solution suggestions wanted!! [7:6579]
- Original Message - From: "Sam Deckert" > The problem is the client wants to use DHCP, so that people in the offices > can simply plug in and away they go. But how would you go about > implementing a DHCP server in this situation?? In order to allocate an > address from the appropriate range, the DHCP server needs to be aware of the > VLAN that the client DHCP request came from. I have not been able to find a > DHCP server that has this capability whatsoever. I am sure this has been > done before - does anyone know how or have any suggestions?? At the edge of each VLAN, an instance of router subinterface is obviously needed. You can configure at each subinterface ip helper address pointing to a real dhcp server located anywhere. Router then forwards any dhcp requests broadcasted by stations in vlans with apopriate subnet info, that dhcp server can use a defined scope for each vlan. Server than answers with lease data to the requestor via directed broadcast. (im not sure if such way) For example NT dhcp server service works flawlessy with such topology, with many different scopes. Pawel/ Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=6581&t=6579 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579]
We have a configuration at our company that has the same configuration as you just described. But somewhere along the line .. This doesn't seem to work that well. We got about 4 vlans, all vlan interfaces have an ip helper address to our DHCP server. Problem is that 8 out of 10 times, a DHCP client doesn't get an ip address. We used an Windows NT server as DHCP but also Nortel's NetID. Both systems give the same problems. Some times a user moves from one vlan to the other but gets an ip address from the old vlan he was in before he did a DHCP request for his new VLAN. We have been trying to find the solution but didn't succeed sofar, maybe somebody had this before and is willing to share it with me. We use a Cisco cat 6500 to handle to forwarding to the DHCP server and the VLAN routing, as access switches we have Cisco cat 3500. Thnx in advance, JT -Original Message- From: Pawel Sikora [mailto:[EMAIL PROTECTED]] Sent: donderdag 31 mei 2001 10:49 To: [EMAIL PROTECTED] Subject: Re: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] - Original Message - From: "Sam Deckert" > The problem is the client wants to use DHCP, so that people in the > offices can simply plug in and away they go. But how would you go > about implementing a DHCP server in this situation?? In order to > allocate an address from the appropriate range, the DHCP server needs > to be aware of the > VLAN that the client DHCP request came from. I have not been able to > find a > DHCP server that has this capability whatsoever. I am sure this has > been done before - does anyone know how or have any suggestions?? At the edge of each VLAN, an instance of router subinterface is obviously needed. You can configure at each subinterface ip helper address pointing to a real dhcp server located anywhere. Router then forwards any dhcp requests broadcasted by stations in vlans with apopriate subnet info, that dhcp server can use a defined scope for each vlan. Server than answers with lease data to the requestor via directed broadcast. (im not sure if such way) For example NT dhcp server service works flawlessy with such topology, with many different scopes. Pawel/ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=6582&t=6579 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579]
Try using DHCPLOC to monitor DHCP requests/replies traffic. This will give you an indication as to why clients can not lease IP addresses. I believe the reason why clients that move from one VLAN to another keep getting the same IP address is because they are trying to renew the existing IP address. Those clients need to release their IP addresses before attempting to obtain a new one: IPCONFIG /RELEASE; IPCONFIG /RENEW CM > -Original Message- > From: Jeroen Timmer [mailto:[EMAIL PROTECTED]] > Sent: 31 May 2001 10:03 > To: [EMAIL PROTECTED] > Subject: RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] > > > We have a configuration at our company that has the same > configuration as > you just described. > But somewhere along the line .. This doesn't seem to work that well. > > We got about 4 vlans, all vlan interfaces have an ip helper > address to our > DHCP server. Problem is that 8 out of 10 times, a DHCP client > doesn't get an > ip address. We used an Windows NT server as DHCP but also > Nortel's NetID. > Both systems give the same problems. > Some times a user moves from one vlan to the other but gets > an ip address > from the old vlan he was in before he did a DHCP request for > his new VLAN. > > We have been trying to find the solution but didn't succeed > sofar, maybe > somebody had this before and is willing to share it with me. > > We use a Cisco cat 6500 to handle to forwarding to the DHCP > server and the > VLAN routing, as access switches we have Cisco cat 3500. > > > Thnx in advance, > > JT > > -Original Message----- > From: Pawel Sikora [mailto:[EMAIL PROTECTED]] > Sent: donderdag 31 mei 2001 10:49 > To: [EMAIL PROTECTED] > Subject: Re: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] > > > - Original Message - > From: "Sam Deckert" > > > The problem is the client wants to use DHCP, so that people in the > > offices can simply plug in and away they go. But how would you go > > about implementing a DHCP server in this situation?? In order to > > allocate an address from the appropriate range, the DHCP > server needs > > to be aware of > the > > VLAN that the client DHCP request came from. I have not > been able to > > find > a > > DHCP server that has this capability whatsoever. I am sure > this has > > been done before - does anyone know how or have any suggestions?? > > At the edge of each VLAN, an instance > of router subinterface is obviously needed. > You can configure at each subinterface > ip helper address pointing to a real dhcp > server located anywhere. > Router then forwards any dhcp requests > broadcasted by stations in vlans with > apopriate subnet info, that dhcp server can > use a defined scope for each vlan. > Server than answers with lease data to the > requestor via directed broadcast. > (im not sure if such way) > > For example NT dhcp server service > works flawlessy with such topology, > with many different scopes. > > Pawel/ > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=6588&t=6579 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579]
We did everything you described below .. We sniffered the network, we saw that the client didn't get a reply from the DHCP server. But what the cause is that the client doesn't get a reply .. We couldn't find out. We also tried to release the client's ip address by ipconfig /release etc. etc. This also didn't work, I had to delete the client in the DHCP scope of NetID (where I found that client with his old ip address and sometimes had to remove it several times) to let the client get a new ip address by releasing his old ip address. We used the NetID server for DHCP, even changed to a WinNT server to do DHCP, but the problem still remains. The thing we have configured in the router is only an ip-helper address on each VLAN interface. What about the ip dhcp-server command ... Do you have to configure that one to ? With kind regards, Jeroen Timmer -Original Message- From: Charles Manafa [mailto:[EMAIL PROTECTED]] Sent: donderdag 31 mei 2001 11:47 To: [EMAIL PROTECTED] Subject: RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] Try using DHCPLOC to monitor DHCP requests/replies traffic. This will give you an indication as to why clients can not lease IP addresses. I believe the reason why clients that move from one VLAN to another keep getting the same IP address is because they are trying to renew the existing IP address. Those clients need to release their IP addresses before attempting to obtain a new one: IPCONFIG /RELEASE; IPCONFIG /RENEW CM > -Original Message- > From: Jeroen Timmer [mailto:[EMAIL PROTECTED]] > Sent: 31 May 2001 10:03 > To: [EMAIL PROTECTED] > Subject: RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] > > > We have a configuration at our company that has the same > configuration as > you just described. > But somewhere along the line .. This doesn't seem to work that well. > > We got about 4 vlans, all vlan interfaces have an ip helper > address to our > DHCP server. Problem is that 8 out of 10 times, a DHCP client > doesn't get an > ip address. We used an Windows NT server as DHCP but also > Nortel's NetID. > Both systems give the same problems. > Some times a user moves from one vlan to the other but gets > an ip address > from the old vlan he was in before he did a DHCP request for > his new VLAN. > > We have been trying to find the solution but didn't succeed > sofar, maybe > somebody had this before and is willing to share it with me. > > We use a Cisco cat 6500 to handle to forwarding to the DHCP > server and the > VLAN routing, as access switches we have Cisco cat 3500. > > > Thnx in advance, > > JT > > -----Original Message- > From: Pawel Sikora [mailto:[EMAIL PROTECTED]] > Sent: donderdag 31 mei 2001 10:49 > To: [EMAIL PROTECTED] > Subject: Re: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] > > > - Original Message - > From: "Sam Deckert" > > > The problem is the client wants to use DHCP, so that people in the > > offices can simply plug in and away they go. But how would you go > > about implementing a DHCP server in this situation?? In order to > > allocate an address from the appropriate range, the DHCP > server needs > > to be aware of > the > > VLAN that the client DHCP request came from. I have not > been able to > > find > a > > DHCP server that has this capability whatsoever. I am sure > this has > > been done before - does anyone know how or have any suggestions?? > > At the edge of each VLAN, an instance > of router subinterface is obviously needed. > You can configure at each subinterface > ip helper address pointing to a real dhcp > server located anywhere. > Router then forwards any dhcp requests > broadcasted by stations in vlans with > apopriate subnet info, that dhcp server can > use a defined scope for each vlan. > Server than answers with lease data to the > requestor via directed broadcast. > (im not sure if such way) > > For example NT dhcp server service > works flawlessy with such topology, > with many different scopes. > > Pawel/ > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=6590&t=6579 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Weird DHCP/VLAN solution suggestions wanted!! [7:6579]
I ran into a similar problem with a 4006 using the 4232-L3 with 3524XL's in the closet. You could see the DHCP request come accross to the server but the server never would reply. For the 4232-L3, there's a known DHCP bug (even in the latest code) regarding address rewriting when forwarding the DHCP request in the event the DHCP server's primary pool for that subnet is unavailble. This bug concerns the forwarding of packets, not the 4232-L3 acting as a DHCP server itself. Not sure how far this bug might reach. Tighe assignment from the propper pool should the primary pool be unavailble. Jeroen Timmer wrote: > We did everything you described below .. We sniffered the network, we saw > that the client didn't get a reply from the DHCP server. > > But what the cause is that the client doesn't get a reply .. We couldn't > find out. We also tried to release the client's ip address by ipconfig > /release etc. etc. This also didn't work, I had to delete the client in the > DHCP scope of NetID (where I found that client with his old ip address and > sometimes had to remove it several times) to let the client get a new ip > address by releasing his old ip address. > > We used the NetID server for DHCP, even changed to a WinNT server to do > DHCP, but the problem still remains. > > The thing we have configured in the router is only an ip-helper address on > each VLAN interface. What about the ip dhcp-server command ... Do you have > to configure that one to ? > > With kind regards, > > Jeroen Timmer > > -Original Message- > From: Charles Manafa [mailto:[EMAIL PROTECTED]] > Sent: donderdag 31 mei 2001 11:47 > To: [EMAIL PROTECTED] > Subject: RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] > > Try using DHCPLOC to monitor DHCP requests/replies traffic. This will give > you an indication as to why clients can not lease IP addresses. > > I believe the reason why clients that move from one VLAN to another keep > getting the same IP address is because they are trying to renew the existing > IP address. Those clients need to release their IP addresses before > attempting to obtain a new one: IPCONFIG /RELEASE; IPCONFIG /RENEW > > CM > > > -----Original Message- > > From: Jeroen Timmer [mailto:[EMAIL PROTECTED]] > > Sent: 31 May 2001 10:03 > > To: [EMAIL PROTECTED] > > Subject: RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] > > > > > > We have a configuration at our company that has the same > > configuration as > > you just described. > > But somewhere along the line .. This doesn't seem to work that well. > > > > We got about 4 vlans, all vlan interfaces have an ip helper > > address to our > > DHCP server. Problem is that 8 out of 10 times, a DHCP client > > doesn't get an > > ip address. We used an Windows NT server as DHCP but also > > Nortel's NetID. > > Both systems give the same problems. > > Some times a user moves from one vlan to the other but gets > > an ip address > > from the old vlan he was in before he did a DHCP request for > > his new VLAN. > > > > We have been trying to find the solution but didn't succeed > > sofar, maybe > > somebody had this before and is willing to share it with me. > > > > We use a Cisco cat 6500 to handle to forwarding to the DHCP > > server and the > > VLAN routing, as access switches we have Cisco cat 3500. > > > > > > Thnx in advance, > > > > JT > > > > -Original Message- > > From: Pawel Sikora [mailto:[EMAIL PROTECTED]] > > Sent: donderdag 31 mei 2001 10:49 > > To: [EMAIL PROTECTED] > > Subject: Re: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] > > > > > > - Original Message - > > From: "Sam Deckert" > > > > > The problem is the client wants to use DHCP, so that people in the > > > offices can simply plug in and away they go. But how would you go > > > about implementing a DHCP server in this situation?? In order to > > > allocate an address from the appropriate range, the DHCP > > server needs > > > to be aware of > > the > > > VLAN that the client DHCP request came from. I have not > > been able to > > > find > > a > > > DHCP server that has this capability whatsoever. I am sure > > this has > > > been done before - does anyone know how or have any suggestions?? > > > > At the edge of each VLAN, an instance > > of router subinterface is obviously needed. > > You can configure at each subinterface > > ip h
RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579]
There's a bug in Cat IOS code 12.1.4 (I think) which can cause the problems you're mentioning. Did you try an upgrade? The bug ID is CSCds89040 and it's related to HSRP configs and IOS 12.1(4)E. The bug prevents the correct MLS flows from being created. An IOS upgrade fixed my similar problem right away. Vijay Ramcharan -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Jeroen Timmer Sent: Thursday, May 31, 2001 6:15 AM To: [EMAIL PROTECTED] Subject: RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] We did everything you described below .. We sniffered the network, we saw that the client didn't get a reply from the DHCP server. But what the cause is that the client doesn't get a reply .. We couldn't find out. We also tried to release the client's ip address by ipconfig /release etc. etc. This also didn't work, I had to delete the client in the DHCP scope of NetID (where I found that client with his old ip address and sometimes had to remove it several times) to let the client get a new ip address by releasing his old ip address. We used the NetID server for DHCP, even changed to a WinNT server to do DHCP, but the problem still remains. The thing we have configured in the router is only an ip-helper address on each VLAN interface. What about the ip dhcp-server command ... Do you have to configure that one to ? With kind regards, Jeroen Timmer -Original Message- From: Charles Manafa [mailto:[EMAIL PROTECTED]] Sent: donderdag 31 mei 2001 11:47 To: [EMAIL PROTECTED] Subject: RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] Try using DHCPLOC to monitor DHCP requests/replies traffic. This will give you an indication as to why clients can not lease IP addresses. I believe the reason why clients that move from one VLAN to another keep getting the same IP address is because they are trying to renew the existing IP address. Those clients need to release their IP addresses before attempting to obtain a new one: IPCONFIG /RELEASE; IPCONFIG /RENEW CM > -Original Message- > From: Jeroen Timmer [mailto:[EMAIL PROTECTED]] > Sent: 31 May 2001 10:03 > To: [EMAIL PROTECTED] > Subject: RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] > > > We have a configuration at our company that has the same configuration > as you just described. > But somewhere along the line .. This doesn't seem to work that well. > > We got about 4 vlans, all vlan interfaces have an ip helper address to > our DHCP server. Problem is that 8 out of 10 times, a DHCP client > doesn't get an > ip address. We used an Windows NT server as DHCP but also > Nortel's NetID. > Both systems give the same problems. > Some times a user moves from one vlan to the other but gets > an ip address > from the old vlan he was in before he did a DHCP request for > his new VLAN. > > We have been trying to find the solution but didn't succeed sofar, > maybe somebody had this before and is willing to share it with me. > > We use a Cisco cat 6500 to handle to forwarding to the DHCP server and > the VLAN routing, as access switches we have Cisco cat 3500. > > > Thnx in advance, > > JT > > -----Original Message----- > From: Pawel Sikora [mailto:[EMAIL PROTECTED]] > Sent: donderdag 31 mei 2001 10:49 > To: [EMAIL PROTECTED] > Subject: Re: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] > > > - Original Message - > From: "Sam Deckert" > > > The problem is the client wants to use DHCP, so that people in the > > offices can simply plug in and away they go. But how would you go > > about implementing a DHCP server in this situation?? In order to > > allocate an address from the appropriate range, the DHCP > server needs > > to be aware of > the > > VLAN that the client DHCP request came from. I have not > been able to > > find > a > > DHCP server that has this capability whatsoever. I am sure > this has > > been done before - does anyone know how or have any suggestions?? > > At the edge of each VLAN, an instance > of router subinterface is obviously needed. > You can configure at each subinterface > ip helper address pointing to a real dhcp > server located anywhere. > Router then forwards any dhcp requests > broadcasted by stations in vlans with > apopriate subnet info, that dhcp server can > use a defined scope for each vlan. > Server than answers with lease data to the > requestor via directed broadcast. > (im not sure if such way) > > For example NT dhcp server service > works flawlessy with such topology, > with many different scopes. > > Pawel/ > FAQ, list archives, and subscription info: > http://www
RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579]
A comment or two within: -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Jeroen Timmer Sent: Thursday, May 31, 2001 2:03 AM To: [EMAIL PROTECTED] Subject:RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] We have a configuration at our company that has the same configuration as you just described. But somewhere along the line .. This doesn't seem to work that well. We got about 4 vlans, all vlan interfaces have an ip helper address to our DHCP server. Problem is that 8 out of 10 times, a DHCP client doesn't get an ip address. We used an Windows NT server as DHCP but also Nortel's NetID. Both systems give the same problems. Some times a user moves from one vlan to the other but gets an ip address from the old vlan he was in before he did a DHCP request for his new VLAN. CL: unfortunately, windoze does not release ip addresses upon shutdown. Windows machines tend to retain the ip address acquired as long as the lease time has not expired. And sometimes even longer. I've run into problems with mobile users, who upon returning to the office find themselves using and ip address that has been reassigned. This is a windows problem, a "feature" if you will. We have been trying to find the solution but didn't succeed sofar, maybe somebody had this before and is willing to share it with me. We use a Cisco cat 6500 to handle to forwarding to the DHCP server and the VLAN routing, as access switches we have Cisco cat 3500. CL: I ask because I do not know: does the "router" function of the 65xx actually behave the way it is supposed to? Thnx in advance, JT -Original Message- From: Pawel Sikora [mailto:[EMAIL PROTECTED]] Sent: donderdag 31 mei 2001 10:49 To: [EMAIL PROTECTED] Subject: Re: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] - Original Message - From: "Sam Deckert" > The problem is the client wants to use DHCP, so that people in the > offices can simply plug in and away they go. But how would you go > about implementing a DHCP server in this situation?? In order to > allocate an address from the appropriate range, the DHCP server needs > to be aware of the > VLAN that the client DHCP request came from. I have not been able to > find a > DHCP server that has this capability whatsoever. I am sure this has > been done before - does anyone know how or have any suggestions?? At the edge of each VLAN, an instance of router subinterface is obviously needed. You can configure at each subinterface ip helper address pointing to a real dhcp server located anywhere. Router then forwards any dhcp requests broadcasted by stations in vlans with apopriate subnet info, that dhcp server can use a defined scope for each vlan. Server than answers with lease data to the requestor via directed broadcast. (im not sure if such way) For example NT dhcp server service works flawlessy with such topology, with many different scopes. Pawel/ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=6610&t=6579 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579]
Guys, there is something very WRONG here i have a 6509 on site a single DHCP server ..various VLans and never miss an renew are you using the ip helper address properly...( i Mean NO offence)...what i mean is setting a range ip helper address 10.0.*.* to 193.194.199.9 if so check the lease`s on the DHCP server... i need some more info to help i recon your DHCP server is up the swanyare there enough addresses in the scope for all users... (someone i know set up a scope with 1 ip address in to and wondered why only one client got a renew) you only need the ip dhcp command if you want to 65 to BECOME the Dhcp server...(don`t do it it`s a nightmare to adiminster)... please post MSFC configs for inspection HTH steve >From: "Chuck Larrieu" >Reply-To: "Chuck Larrieu" >To: [EMAIL PROTECTED] >Subject: RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] >Date: Thu, 31 May 2001 10:06:06 -0400 > >A comment or two within: > >-Original Message- >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of >Jeroen Timmer >Sent: Thursday, May 31, 2001 2:03 AM >To:[EMAIL PROTECTED] >Subject: RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] > >We have a configuration at our company that has the same configuration as >you just described. >But somewhere along the line .. This doesn't seem to work that well. > >We got about 4 vlans, all vlan interfaces have an ip helper address to our >DHCP server. Problem is that 8 out of 10 times, a DHCP client doesn't get >an >ip address. We used an Windows NT server as DHCP but also Nortel's NetID. >Both systems give the same problems. >Some times a user moves from one vlan to the other but gets an ip address >from the old vlan he was in before he did a DHCP request for his new VLAN. > >CL: unfortunately, windoze does not release ip addresses upon shutdown. >Windows machines tend to retain the ip address acquired as long as the >lease >time has not expired. And sometimes even longer. I've run into problems >with >mobile users, who upon returning to the office find themselves using and ip >address that has been reassigned. This is a windows problem, a "feature" if >you will. > >We have been trying to find the solution but didn't succeed sofar, maybe >somebody had this before and is willing to share it with me. > >We use a Cisco cat 6500 to handle to forwarding to the DHCP server and the >VLAN routing, as access switches we have Cisco cat 3500. > >CL: I ask because I do not know: does the "router" function of the 65xx >actually behave the way it is supposed to? > > >Thnx in advance, > >JT > >-Original Message- >From: Pawel Sikora [mailto:[EMAIL PROTECTED]] >Sent: donderdag 31 mei 2001 10:49 >To: [EMAIL PROTECTED] >Subject: Re: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] > > >- Original Message - >From: "Sam Deckert" > > > The problem is the client wants to use DHCP, so that people in the > > offices can simply plug in and away they go. But how would you go > > about implementing a DHCP server in this situation?? In order to > > allocate an address from the appropriate range, the DHCP server needs > > to be aware of >the > > VLAN that the client DHCP request came from. I have not been able to > > find >a > > DHCP server that has this capability whatsoever. I am sure this has > > been done before - does anyone know how or have any suggestions?? > >At the edge of each VLAN, an instance >of router subinterface is obviously needed. >You can configure at each subinterface >ip helper address pointing to a real dhcp >server located anywhere. >Router then forwards any dhcp requests >broadcasted by stations in vlans with >apopriate subnet info, that dhcp server can >use a defined scope for each vlan. >Server than answers with lease data to the >requestor via directed broadcast. >(im not sure if such way) > >For example NT dhcp server service >works flawlessy with such topology, >with many different scopes. > >Pawel/ >FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] >FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=6635&t=6579 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Weird DHCP/VLAN solution suggestions wanted!! [7:6579]
Thanks for all your answers guys! Its now all goodI checked out the RFC as someone suggested earlier in this group as well. Thanks!! - Original Message - From: "Chuck Larrieu" To: Sent: Friday, June 01, 2001 12:06 AM Subject: RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] > A comment or two within: > > -Original Message- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of > Jeroen Timmer > Sent: Thursday, May 31, 2001 2:03 AM > To: [EMAIL PROTECTED] > Subject: RE: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] > > We have a configuration at our company that has the same configuration as > you just described. > But somewhere along the line .. This doesn't seem to work that well. > > We got about 4 vlans, all vlan interfaces have an ip helper address to our > DHCP server. Problem is that 8 out of 10 times, a DHCP client doesn't get an > ip address. We used an Windows NT server as DHCP but also Nortel's NetID. > Both systems give the same problems. > Some times a user moves from one vlan to the other but gets an ip address > from the old vlan he was in before he did a DHCP request for his new VLAN. > > CL: unfortunately, windoze does not release ip addresses upon shutdown. > Windows machines tend to retain the ip address acquired as long as the lease > time has not expired. And sometimes even longer. I've run into problems with > mobile users, who upon returning to the office find themselves using and ip > address that has been reassigned. This is a windows problem, a "feature" if > you will. > > We have been trying to find the solution but didn't succeed sofar, maybe > somebody had this before and is willing to share it with me. > > We use a Cisco cat 6500 to handle to forwarding to the DHCP server and the > VLAN routing, as access switches we have Cisco cat 3500. > > CL: I ask because I do not know: does the "router" function of the 65xx > actually behave the way it is supposed to? > > > Thnx in advance, > > JT > > -Original Message- > From: Pawel Sikora [mailto:[EMAIL PROTECTED]] > Sent: donderdag 31 mei 2001 10:49 > To: [EMAIL PROTECTED] > Subject: Re: Weird DHCP/VLAN solution suggestions wanted!! [7:6579] > > > - Original Message - > From: "Sam Deckert" > > > The problem is the client wants to use DHCP, so that people in the > > offices can simply plug in and away they go. But how would you go > > about implementing a DHCP server in this situation?? In order to > > allocate an address from the appropriate range, the DHCP server needs > > to be aware of > the > > VLAN that the client DHCP request came from. I have not been able to > > find > a > > DHCP server that has this capability whatsoever. I am sure this has > > been done before - does anyone know how or have any suggestions?? > > At the edge of each VLAN, an instance > of router subinterface is obviously needed. > You can configure at each subinterface > ip helper address pointing to a real dhcp > server located anywhere. > Router then forwards any dhcp requests > broadcasted by stations in vlans with > apopriate subnet info, that dhcp server can > use a defined scope for each vlan. > Server than answers with lease data to the > requestor via directed broadcast. > (im not sure if such way) > > For example NT dhcp server service > works flawlessy with such topology, > with many different scopes. > > Pawel/ > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=6685&t=6579 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
