3750 - Craft Helper Addresses So DHCP Requests Go To Proper Server
Dec 15, 2012
Setting up a stand-alone WDS/PXE server.Current we have helper addresses setup to forward the DHCP requests from the different VLAN's to the DHCP server. The WDS/PXE server we are setting up is on its server. How do we craft the helper addresses so DHCP requests go to the proper server hosting DHCP and PXE requests go the WDS server?
Everything I seen on Microsoft Technet, lists using Helper Address as the recommended way, but assume both services are on the same server. Our helper address is as follows on each VLAN interface in router: ip helper-address X.X.X..This is a Cisco 3750.
Haveing issue with DHCP server handing out IP addresses to client connected to VLAN5 interface.ISP Router>Firewall -(WatchGuard Drop-in mode) I have several 3750 switches and one acting as a L3 switch. The L3 is configured as follow: [code]
If I connect a laptop to int fa1/0/10 I DO NOT get an IP address from the 10.100.0.8 scope. If I connect to another interface within the VLAN 1, I get an address from the 10.100.0.0 range.
I've a Cisco 1941W router which is DHCP server for data-VLANs and uses ip-helper for voice-VLANs. [code] I don't know why I can't have IP from wireless voice VLAN whereas it is OK and wired voice VLAN and conf is the same!
I have a Linksys WAP200 Wireless-G Access Point problem. It is SW version 2.0.4.0. I have it configured for a small network and the problem seems to be that it is not forwarding DHCP requests onto my DHCP server. I know that it is not a SSID or Key issue as when I give my devices static IP addresses, they communicate fine within my system. The only issue seems to be when the devices make DHCP client requests. I also know that the problem is not my DHCP server as it has the device's IP / mac addresses in its configuration file and other wired devices are able to communicate with it to get their IP address through DHCP.
I have seen that there was talk in some blogs about WAP200 no forwarding DHCP requests and I was hoping that updating the device to the latest release would have resolved the problems.
I have several Cata 3500XL switches connected to one 1 HP L3 switch which is connected Sonicwall router. Vlan1 has subnet of 10.10.0.0/24 and Microsoft DCHP server lays inside VLAN1.
Now i want to add VLAN11 (192.168.10.0/24) as second data VLAN but DHCP requests should go to microsoft DCHP server.
This is what i did: Configured VLAN11 IP on each cisco switch IP default gateway with IP from other subnet (i guess this is bad since maybe it should be IP of VLAN11 on HP L3 switch?) Trunk ports are configured to pass everything on cisco switches On VLAN11 i configured IPhelper IP to be MS DHCP server on each Cisco switch
I haven't tested this yet but i have problem in process.I can't ping VLAN11 IPs between switches (i configured VLAN1 and VLAN11 with IP). When client plugs computer to a port that belongs to VLAN11 will i be sure that client will get IP from the 192.168 range or there is possiblity that he gets IP from the management VLAN range?
Had a problem with a 3750 this morning not handing out DHCP addresses. The following is a sanitized config of what the switch is using. [code] The IOS installed on the switch is c3750-ipbasek9-mz.122-55.SE1.bin. What got my attention was that the sh ip dhcp pool PC showed 180 addresses being excluded. In doing the math from the dhcp excluded addresses, only 64 should be excluded.
My next step was to remove the second dhcp excluded-address line above. Doing a clear ip dhcp binding * started letting the DHCP service hand out addresses but the sh ip dhcp pool PC stil showed 180 addresses excluded.
It finally took removing the dhcp pool and putting it back in to drop the number of excluded addresses down to a value that matches the first excluded-address line. Didnt see a dhcp bug in the bug database that would explain this.
I tried re-entering the second excluded-address line from above and saw the number of excluded addresses rise as expected. When I negated the line, the number of excluded addresses dropped back to its previous value.
I imagine I can use the framed-ip-address attribute to assign ip-addresses but there seem to be support for static ip addresses only?A bit of a drag when we're talking 200+ nodes.
I am looking to get a gigabit ethernet adapter for my minecraft server that is quite big now. It used to run off the motherboard but now since its quite big i thought if i should get a good card. It has to be a pci card and compatible with windows 8
I have a LAN with about 200 computers (192.168.10.0/24) with a DHCP Server on Windows server 2003.The problem is that my company have acquired 100 others computers that I have connected on this network.Some computer does not get IP address from the DHCP server. When I investigated the log of the DHCP server, I realized that the DHCP server was out of addresses.
We have a Cisco 5505 ASA fireawll at a remote site. I can get the firewall to issue the IP addresses to the pc's, Is there a way for the pc's to get their IP addresses directly from our DHCP server?
I used to use a CentOS self-made server for intranet for my little office, but I bouth few days ago a Cisco 861 router to replace the linux box.
1. I have 2 public IP classes from my ISP. 1 class is limitted to 80mbit upload, the other to 30mbit upload. So I need some sort of DNAT to be able to know exactly which intranet computer uses big internet and which one limitted internet. 2. I need DHCP server and with static IP addresses (one computer must always have the same IP address, etc).. i have my needs for this. 3. Also I need external access to some servers inside (web, ftp, etc) [code]
So far so good, all looks simple and I can achieve this in 2 hours on a centos linux box (correct routes, ip forwarding enabled and few iptables rules for NAT/SNAT/DNAT).
But on this brand new Centos router well, i'm not even successful in pinging the outside world, nor the inside world I'm tired of reading the forums, the documentation..i want (at first) a simple scenario: vlan+dhcp, fa4 with 1 public ip address and ACCESS to the real world. I wasn't able to achieve not even that much. [code]
I currently have DCHP server set up on my new 1141N. Everything works great, but I wanted to know if it were possible to make the DHCP server only hand out ip addresses on the wireless connection? Currently the AP is giving out ip addresses from the pool to wired and wireless pc's.
I upgraded my SG500 switch firmware to 1.3.0.59, since there is a new functionality DHCP server v.4 well I must say I came accross the issue I cannot solve. DHCP server assign dynamic address - no hassles. troubles start with static IP hosts.I defined a couple of hosts with static address within the correct subnet. I tried with hardware address and client identifiers. no luck. my switch does not assign the IP address I assigned to the suitable mac address. to define it I use both CLI & Web.
ip dhcp pool host HP-Elliteaddress 10.10.11.7 255.255.255.0 client-identifier 01:d8:d3:85:cf:09:72client-name HP-Ellitedefault-router 10.10.11.1exit ip dhcp pool host VAIO-Zaddress 10.10.14.108 255.255.255.0 hardware-address 54:53:ed:1c:a1:46 default-router 10.10.14.1exit
Cisco PIX Security Appliance Software Version 8.0(2) Device Manager Version 6.1(5)51
Cisco PIX Security Appliance Software Version 8.0(2)Device Manager Version 6.1(5)51 Running VPN on this device with an internal DHCP Pool tunnel-group JVusergroup type remote-accesstunnel-group JVusergroup general-attributesaddress-pool JVusergroup-DHCP-Pool I would like to use an external DHCP insted of the pix itselvf. How do I relay (IP-helper) DHCP request on the VPN policy to an external DHCP-server?
Version 12.2(33)SXI int vlan 1 description client vlan ip vrf forwarding A ip address 10.1.1.1 255.255.255.0 standby 129 ip 10.1.1.2 standby 129 timers 1 4 standby 129 priority 105 standby 129 preempt ip helper-address 10.1.2.20
[code]....
dhcp requests are not making it to the dhcp server SAME VRF (ip helper-addres is not doing anything.....)extended vrf traceroutes on udp 67 sourced from vlan2 are fine
I am expecting udp unicast packets on port 67 "giaddr" relay packets on the DHCP server generated and sourced by the relay on Vlan1
eg. Mar 1 01:59:06.731: DHCPD: setting giaddr to 10.1.1.1
This exact setup works in our preprod environment with the same code.Only difference is we run Distributed etherchannel on the 6500's where this doesnt work.
Wireshark on the client I can see the requests being sent Going to check it with debug ip dhcp server to check the relay logs out of production hours.
I have seen so many people say it IS and ISN'T supported on this version of the code.e.g. [URL]
I am aware the helper-adddress should inherit the vrf of the interface ip helper-address vrf command is not supported.The fact it works in the PP environment.... could this be due to the Distributed EtherChanel difference? or just some bug....
1 x 4500 and 1 x 3560?They are gateways of 8 Vlans?They are doing HSRP in each of those Vlans?The 4500 is the Active?There is a DHCP Pool for each of those Vlans on both gateways using "ip dhcp excluded-address" I ensured that the range of provided ips by each DHCP server will not be overlapped Obs.: Reducing the lease time, I ended with the calls bringing related problems.
OK, every thing is blue, every thing is fine.But the network diagram is realy complex(41 switchs, 89 uplinks), and depending of how is the network flow, one or other server answer first or latter.
For many reasons I would like that the secondary DHCP server would answer only if the primary DHCP server goes down.To me, the bigger reason is that DHCP database would be only in one DHCP server.But there is other reasons.
I passed by many frustrated solutions:Try to force a delay on the answer on one of the servers. - Impossible.Try to disable DHCP server, and, using EEM, enable it only if router became active in HSRP. - I couldn't do It.
What I'm thinking now is use the HSRP resource to resolve it.On both routers I would put a "ip helper-address" pointing to an Virtual_HSRP_IP.And depending on which router is the active, him will answer the request.
My first doubt is:Would it work?The second doubt is:Could I use the same Virtual_HSRP_IP that exists on that Vlan(see example 1),or I would need to point it to a Virtual_HSRP_IP in a different Vlan(see example 2)?
Example 1 ----------------------------------- | 4500 | ----------------------------------- interface Vlan1 ip address 10.10.0.2 255.255.0.0 ip helper-address 10.10.0.1 standby 1 ip 10.10.0.1
I have a WCS that I use to manage 8 controllers (2 WiSM's totaling 4 controllers, and 4 more controllers at remote locations). All controllers connect to 3750 switches. The layer three interfaces for all V LAN's that are related to the wireless network are created on these switches. Each layer three interface has a helper address that points the devices in the sub net to the correct DHCP server.
When a wireless device requests a DHCP request I believe it gets to that server based on the relay from the layer three interface on the 3750. However, I know that the virtual interface on the controller is also requesting an address because my firewall is flooded with deny statements. The virtual interface is configured for 1.1.1.1 and so it gets blocked. I am starting to question the use of this interface considering the fact that it is getting blocked and the clients are still getting address.
Are both interfaces trying to act as DHCP relays? Could I setup the controllers to be the only relay (without using the virtual interface)?
a power analyzer in my network is sending some packets that are unexpected and incorrectly recognized as DHCPOFFERS. As a workaround, I would like to filter those packets with my Cisco switch 3750.Suppose IP_POWER_ANALYZER is the ip address, what could be the best choice
1. deny udp any IP_POWER_ANALYZER eq bootpc 2. deny udp any IP_POWER_ANALYZER eq bootpc; deny udp IP_POWER_ANALYZER any eq bootps 3. deny udp any eq bootpc IP_POWER_ANALYZER eq bootps
I have customer who has as Core Switch one Cisco Catalyst 3750 with the IOS c3750-ipbase-mz.122-35.SE5.I know that this image support DHCP Server configuration, but I like to implementate new vlans (approx 15) and I want to know if this switch support 15 DHCP Servers.
I have a 1250 AP connected to an Switch Cisco 3750. We have a SSID(v lan 1 - native) which get an IP Address from our DHCP Server(located in a Windows 2003 server). I added a new SSID in VLAN 2 and I would like no to use the DHCP Server but to make the AP get an IP Address from the pool I created in the own AP (ip dhcp pool Guest) but every time I try to connect the new v lan, it doesn't get an ip address.
Follow the settings of the AP.
version 12.4 no service pad service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption [Code]...
I have been looking at the Cisco Hardware docs and I can't find anything on the proper way to setup a 2 switch stack for Stackwise redundancy and Stackpower redundancy. Everything details 3 or more switches.
I am trying out a DAP-1513 unit but there is no forum section for this? My question seems to be general and might cover the other models also. Do the DHCP request, from the attached LAN devices on the DAP, get pass to the DHCP "server?"
a new LAN installation, two VSS pair 6509 core, 15 closets, with 3750 stacks. Floor 15 only, devices/hosts can ping teh DHCP server but cannot aquire IP addresses. no such problem on other floors?
I have a 2911 router connected to a 3750 switch. I have configured vlan interfaces on the 2911 router:I am using the vlan 89 (89.2) as the management ip address for me to remotely get to the switch. Is this a proper configuration or could this cause issues in the future.
We have an 1140N AP connected to a switch and our "network partner" controls the router and will hand out DHCP and do the NAT for this WLAN. How can I configure the AP to forward DCHP requests through.
I have WPA2 PSK (TKIP) setup and the client is able to authenticate however we fail to get an address. In this case the Ethernet interface was left alone so it has the default config and it gets a DHCP address fine. How can I configure this AP to enable the rest of the WiFI clients to get an IP?
I have 2 1242AG APs setup with one SSID and no vlans configured. The APs are connected to a switch along with my DHCP server. Clients are able to connect to the SSID but are unable to get an IP from the server. Clients can plug into the switch and get an IP. If I configure a static IP on the wireless card, the client works fine.
Is there something I'm missing on the AP to allow DHCP requests to pass through? IPhelper?
Here is the AP info: AIR-AP1242AG-A-K9 12.4(21a)JA1
Cisco Small Business Switch POE ESW-520-24P with a Wireless Access Point Cisco Aironet AP1141. Both the devices are upgraded to the latest firmware.
Connected to the ESW-520-24P is a Windows 2008 SBS 2011 with DCHP and Domain Controller. Along with the server I have a number of wired computers connected to the switch which do not have any issues and connect to the DHCP server without any problems.
When connecting two wireless devices to the AP1141, they get the IP address and DHCP from the server; but when connecting other devices apart the first two they will fail to connect to the DHCP server and do not get any IP Address. They manage to connect to the Wireless access point but they cannot contact the DHCP server.
I have a school with 550 iPads. We are using two 5508 WLCs sharing the number of APs. The DHCP server and the default gateway for the network are on the firewall. The clients are able to get a DCHP. After some time, maybe about longer than a month, the clients are no longer able to get DCHP addresses. A reboot of both controllers takes care of this. Presently we are runing 7.2.110 OS. I am going to upgrade to the latest 7.4.100, and reload tonight.
We have setup a bridge between two of our offices using two WET200's in adhoc mode. Everything is connected fine and the signal strengh is good. All traffic pass's over the bridge correctly but DHCP requsts/replys seem to be failing to traverse the bridge. Our DHCP server is hosted on site A and the computers on site B fail to obtain thiers IP's from the dhcp over the bridge requiring us to use static IP's.Firmware is currently the latest.
I have a sg200-18 connected via one of the ports to my ISP's router/modem. Using an unmanaged switch everything works as expected, but after a few days on my sg200 my two computers fail to get assigned IP's and cannot connect to anything. I also have a couple printers that seem to have no problems getting their IP's passed through to the router as I can use them fine from my machines when connected to the unmanaged switch.
Is there a possibility I don't have my switch setup properly to know that all outgoing data must go to the router, or UDP traffic is being dropped somehow?
