Cisco Switching/Routing :: 881 - Blocking DHCP Requests Of Windows Clients?
Nov 18, 2012
We've got 5 remote offices with cisco 881 routers, Win Clients behind them and all routers connected via vpn site-to-site to central software router.
Mostly all clients recieve ip addresses from routers in their subnets 192.168.x.024
We have Win DHCP Server in subnet 192.168.181.024
The problem is that some of clients,physically sutuated in 192.168.10.024 subnet, recieve ip addresses from Win DHCP server from 192.168.181.024 subnet.
Here's part of cisco cfg:
interface FastEthernet0
no ip address
!
interface FastEthernet1
[Code].....
View 3 Replies
ADVERTISEMENT
Dec 14, 2011
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.
View 17 Replies
View Related
Jan 10, 2012
I have two 3560x Catalyst switches setup between two different locations. They link via a PTP line (Layer 2). I have setup Intervlan routing between the switches and that works fine.Each location has a separate subnet and a Windows DHCP server for each subnet.I want to block any DHCP requests to be sent from hosts on one subnet to the DHCP server on the other side (i.e across the PTP link) What is the best method to do this?
View 5 Replies
View Related
Jul 18, 2012
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?
View 4 Replies
View Related
Nov 11, 2011
I was trying to find if it's possible to add the option for static routes for DHCP clients on Cisco IOS DHCP config mode. I'm looking to add a settings as defined on RFC 3442, like this one, set on ISC DHCPd server:
Global settings:
option rfc3442-classless-static-routes code 121 = array of integer 8;
option ms-classless-static-routes code 249 = array of integer 8;
And for the subnet declaration:
option rfc3442-classless-static-routes 24, 192, 168, 30, 192, 168, 10, 1;
option ms-classless-static-routes 24, 192, 168, 30, 92, 168, 10, 1;
View 5 Replies
View Related
Jan 6, 2013
I've just discovered this thing in Windows Event log. The DHCP-Client log is full with this: the client received a NAK from the DHCP Server. Strangely, they still get the desired IP address. (Which are reserved adresses for the MAC adresses.)So I've looked at the logs in the DIR-615 (rev.D, FW: 4.13), and found this:
View 1 Replies
View Related
Mar 27, 2012
I have trouble with a Cisco 892 Router from my Internet service provider.
Last week we switched from a virtual Router to a hardware Router. But after plugging it in our LAN Switch, the Windows DHCP Server stopped leasing IP's. I got many BAD_ADDRESS with MAC like e1:80:10:ac, e2:80:10:ac, e3:80:10:ac, e4:80:10:ac, e5:80:10:ac, ea:80:10:ac, eb:80:10:ac, ec:80:10:ac and so on.
I do not have access to the Router config, so I can not dump the config to you. We have a flat LAN, single SUB-Net(172.16.0.0/16) and no VLAN, no Spanning Tree. A Keep it Simple, Stupid(KISS) System.
A tech guy from service provider, is telling us, the error is not there fault and my switch is not correctly configured. But this is ********. For years we had a another Cisco Router from the precursor ISP and for 2 years the virtual Router from our current ISP. No trouble with my DHCP. But after plugging the new Router in, my DHCP stopped working.On the 892 is no running DHCP, but something interferences with my Windows Server 2008 R2 SP1 DHCP Server.
View 15 Replies
View Related
Oct 30, 2012
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?
View 6 Replies
View Related
Jun 10, 2010
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
View 7 Replies
View Related
Dec 7, 2011
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?"
View 6 Replies
View Related
Feb 15, 2013
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.
View 1 Replies
View Related
Feb 15, 2012
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.
View 3 Replies
View Related
Dec 15, 2010
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.
View 1 Replies
View Related
May 30, 2013
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?
View 7 Replies
View Related
Jul 7, 2012
i have several cisco 3500XL switches with trunking. I created a VLAN lets say 20 which purpose is for wireless clients. I installed wireless controller with 4 APs and controllers sees all 4 APs. Controller is also DCHP server. When wireless client authenticates it's DCHP requests in not getting to DHCP server (controller). If i connect all equipment in non managed switch everything works.
View 10 Replies
View Related
Apr 18, 2013
I'll start out with the fact I work mostly with Wi-Fi and not a lot in the security realm... If I plug my workstation into the 3560, my wired client adapter can get an IP address. But the WLAN adapter will not when associated to WLAN.Usually this is not a problem since you may only have two access points on the controller and a dozen or so hosts. In my case, however, I want to put a few of the ports on the 3560 into the same VLAN as the WLAN on the 2106 so I can give them the same guest access as the WLAN. The hosts plugged into the 3560 get an IP address without issue from the ASA. When I disable dhcp proxy, the WLAN clients get an IP address, but then the APs cannot get an IP address from the internal DHCP server on the WLAN controller, and cease to function when rebooted since they cannot get to the controller without an IP address.
Any way to configure the ASA to accept the modified DHCP packets from the WLAN controller? It appears to me that the ASA is not able to accept DHCP relayed packets.
View 21 Replies
View Related
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.
View 6 Replies
View Related
Nov 11, 2012
I have some DHCP trouble since I subnetted my network with a 2921. My clinets are in 172.16.2.0/23 and DHCP servers are in 172.16.5.0/24.Sometimes, randomly I guess, I get NACK from my DHCP server, and if I look into DHCP logs I got something like this:
15,11/09/12,09:52:27,NACK,172.16.3.172,switchE51D12.host.com,A0CF5BE51D12,,0,6,,,,,,,,
15,11/09/12,09:52:28,NACK,172.16.3.172,switchE51D12.host.com,A0CF5BE51D12,,0,6,,,,,,,,
15,11/09/12,09:52:29,NACK,172.16.3.172,switchE51D12.host.com,A0CF5BE51D12,,0,6,,,,,,,,
[code]....
View 6 Replies
View Related
Apr 3, 2012
Have a client wanting to hand out public ip addresses to all clients from a PFSense Firewall terminating the internet connection.
How do I allow the Cisco Switches currently in place, configured with private ip addresses in the 10.10.x.x ranges and Vlans, where the main 3550 layer 3 has defined dhcp scopes for each vlan, to relay dhcp requests from all vlans to the PFSense firewall?
I assume I would take off the currently defined dhcp scopes for the vlans and configure each vlan/switch with the ip helper address and specify the PFSense firewall and that Nat would have to be disabled onthe firewall?
View 1 Replies
View Related
Apr 19, 2012
I have a 1921 k9 router that has several DHCP pools configured. Before implementing the firewall they were all working. After implementing it they stopped working. I messed around and got the routed port GE0/1 handing out IP addresses and left it alone. Somehow it quit handing out IP addresses yesterday.I dont know if its a quick fix or not (getting DHCP working on the interfaces) but if any article that will walk me through getting DHCP working on all of the interfaces. [code]
View 10 Replies
View Related
Oct 4, 2012
I am using 1841 LAN router. Recently some broadcast is happening in our network when some users are connected. I need to block them automatically by detecting who are they.
I can block them manually but i want router to detect them and block.
View 4 Replies
View Related
Apr 18, 2012
I have a 1921 K9 with a 4 port 10/100/1000 EHWIC switch.
Interface 0/1 = 192.168.1.0
EHWIC = 192.168.5.0
I have Active Directory setup on the 192.168.1.0 network. When I attempt to join the domain from 192.168.5.0 it joins but I get errors. After some troubleshooting using portqry I have found that the services related to class map DomainTrafficUDP are being reported by portqry as being filtered regardless of policy map settings (currently set to allow).
Building configuration...
Current configuration : 18833 bytes
!
! Last configuration change at 11:20:25 NewYork Thu Apr 19 2012 by dave
! NVRAM config last updated at 13:56:45 NewYork Wed Apr 18 2012 by dave
!
[Code].....
View 2 Replies
View Related
Dec 11, 2011
We have a group of computers on their own VLAN. A router allows internet access while keeping them sandboxed. We don't want them accidentally connect to our production network. We blocked their wireless MACs in unauthorized WAPs. I'd like to do the same thing for their ethernet MACs on our switches, (a mixture of 2950,2960 and 2960G currently testing on C2960-LANBASE-M, Version 12.2(25)SEE2). I've been unable to locate the correct method on google, by searching these boards or in the command reference.
What is the best practice for blocking a group of MACs from accessing a particular VLAN on a network consisting of several Layer 2 Switches?
View 4 Replies
View Related
Nov 25, 2012
Blocking Ports don´t send BPDUs, but they can receive them from designated ports.Blocking ports, can it hold BPDUs?
I think that Blocking Ports only receive, analyse and then discard the BPDU.But, what happen if the blocking port receive a better o worse BPDU? in this case, must be the bpdu stored?
View 2 Replies
View Related
Apr 18, 2013
I am looking at buying the EA6500 router. However, before I make the investment into buying this router, I need to know some basic information first.
1. I want to setup the EA6500 to accept FTP requests to my Windows Home Server. Yes or No?
2. Remote access to the EA6500, Yes or No? i am aware of the security risks
3. I need to setup Port forwarding on the EA6500. I assume I can?
4. Manage a Kindle Fire and other wireless devices?
View 5 Replies
View Related
May 30, 2013
I've run into an odd problem - I have connected two 2960s together with copper on FastEthernet interfaces, and STP on the new switch immediately puts that port into blocking mode. I don't understand why this would be, since there is only one connection between the two, in fact, there is only one connection at all on the switch that is blocking.
View 6 Replies
View Related
Sep 24, 2012
I inherited a Cisco ASA 5505 and am trying to piggy back the device off of an established Network. Here is the basic layout:
192.168.10.1 (Core Router - Handles DHCP/DNS)
192.168.10.9 (ASA 5505 - Piggy backing off of Network)
192.168.40.x (ASA 5505 - VLAN)
I'm able to get onto the Internet without any problems. Devices from the 192.168.10x Network can not ping the inside VLAN1 (192.168.40.x). However, I would like traffic going from the inside VLAN to the Outside VLAN to be blocked, except for 192.168.10.1 and 192.168.10.9. I've tried using ACL's but end up killing my Internet connection. 192.168.10.1 is the default route and is how I get out to the Internet. Is this possible? Essentially, I'm trying to set up a small Network that guests can connect to. The idea is that they can get to the Internet, but that is it. They can't get to internal resources on the 192.168.10.x Network
Here is the config:
ASA Version 8.2(1)
!
hostname ciscoasa
enable password EeCsulrpu.9LalEE encrypted
[Code].....
View 5 Replies
View Related
Jun 15, 2013
SG-300 52 native VLAN blocking network packets
View 3 Replies
View Related
Mar 24, 2013
I have a strange issue where spanning-tree is blocking vlans through a mesh network.Here is my set up.
2-Cisco 3560's that have two trunk ports set with do1q and a native vlan of 2. I'm allowing a client vlan (2) and a voice vlan (103) to come over the trunk. They have a native vlan of 2 so the mesh APs can get an address through DHCP. Spanning-tree loop guard is also enabled.
When connected to the mesh network, the voice vlan is being blocked by spanning-tree. I get the following erros:
000129: *Feb 28 19:24:58.289 EST: %SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port FastEthernet0/1 on VLAN0103.000130: *Feb 28 19:24:58.448 EST: %SPANTREE-2-LOOPGUARD_UNBLOCK: Loop guard unblocking port FastEthernet0/1 on VLAN0103.
Eventually the loop is cleared and the port is set back to a forwarding state from a blocking state. I don't want to disabled spanning-tree loopguard since I don't want to create a loop. The mesh network is supposed to act as a P2P connection between two switches. As a test I disconnected the APs from their trunk ports. I then used a cross over cable to connect the switches and no spanning tree loops occured. The mesh doesn't have STP enabled on it and should just be acting as an over-the-air connection from one switch to another.
View 1 Replies
View Related
Jan 29, 2013
We have a Cisco 2911 router in our company. I didn't set it up myself nor I was involved. I only started working here recently, bit over 3 months ago. I have been given ongoing task which other IT Technicians been struggling for almost a year with a idea that maybe because I'm fresh person in the company I will find a original idea why could this thing not work.
Our router have a problem with blocking a single IP address, but not completely It's hard to explain but I will try my best. Company is hosting their website externally and accessing the host and FTP on the host on daily bases. It is important for the website to work on the internal network in company. It does work sometimes, but from time-to-time the website showing time-out error 118 on any point before Cisco router using both http and https, have tried putting just the IP address( doesn't matter is it on the general network or last ISA server on DMZ ). I am able to connect to the website using any of proxy gates but not directly to the website. I have also tested the connection past the router and I was able to connect to the website without any problems. I am also able to ping the host's address from the router and internal network.
I have eliminated the possibility of not correctly setup proxy or firewall on the network as problem also occur on the DMZ. I have also checked access-lists on the router and firewall rules for Any possibilities and I can't really see a way why would the router do this.
View 2 Replies
View Related
Apr 25, 2012
I have a connection between switches, There are a 3560 (Gi0/37) and a 2960 (Gi0/1), the problem is in the port Gi0/37 of the 3560 switch and this is the log. [code]
I dont understand what is the problem, actually i have added the command power inline never on the port and the problem is solved, but we haven´t changed configuration.
View 3 Replies
View Related
Dec 20, 2011
I have a cisco2960 with c2960-lanbasek9-mz.122-50.SE4 imagebase.This switch is connected with 3 unmanaged switches.Though 2960 is managed and only a single vlan is given accessed to connected other unmanaged switches.Problem is this, if at user end, a laptop is connected ( Microsoft Vista OS) and its IPv6 is checked in the LAN properties settings then the laptop's IP address changed from our VLAN to 192.168.100.x series and due to this other connected user's DNS addresses become changed.Hence I want to block this IP or its MAC on Cisco 2960.
View 1 Replies
View Related
Mar 23, 2012
I have a stack of Catalyst 3750E switches.
IOS image :c3750e-ipbasek9-mz.122-55.SE3.bin
I have been seeing multiple occurance of the below message in the switch logs.
"Failed to send hrpc non blocking message"
I could not find a relevant reference for this message in the Cisco.com.
View 4 Replies
View Related
