I've configured ip dhcp snooping on several vlans I want to monitor and the binding table doesn't seem to be building.eature DHCP is on, global ip dhcp snooping is enabled, VLAN snooping is enabled on the vlan's I want to monitor and my trusted interfaces are also configured. Alas no binding entries in the table! 7K is running 4.2(6).
View 1 RepliesI have run into a very strange problem while doing pre-deployment vPC/STP testing in the lab with a pair of Nexus 7000s.
The basic configuration is as follows:
2x Nexus 7000 VDCs (ver 6.0(4)) are configured as vPC peers and connected with a vPC peer-link (redundant on different 10G blades) and a vPC peer-keepalive link. The switches also act as HSRP and EIGRP routers. The N7K-A switch is nominally configured as STP root and HSRP prime for all VLANs, N7K-B switch is STP backup root and HSRP secondary. STP version is PV-RSTP+. As it stands now STP root and vPC prime are on different switches, STP root is on N7K-A and vPC prime is on N7K-B.
3x Layer-2 access switches (3750-1, 3750-2, 3560-1) are configured as access switches and connected to the Nexus 7Ks with a 1G uplinks in V-pattern.
3750-1 and 3560-1 are configured for vPC as Port-Channel10 and Port-Channel12 respectively. 3750-2 is configured for STP. Vlan 35 is shared between all three switches and is enabled on the vPC peer-link (overlapping vPC and STP domains). The downlink port to the STP-only 3750-2 on N7Ks is configured as "vpc orphan suspend".
Everything seems to work fine and pings on VLAN 35 between access switches (that have mgmt interfaces in VLAN35) recover rapidly after failures. However, if I break the vpc peer-link the ping between the two vPC switches 3750-1 and 3560-1 stops. Moreover, this appears to be sporadic in nature with some vpc peer-link failure attempts recreating the problem and some not. Sometimes the problem manifests itself when the peer-link is brought back up rather than taken down.
After doing a bit of troubleshooting, I have isolated the problem to MAC address blackholing. Basically when the peer link is taken down, MAC Address table on the vPC primary switch, N7K-B, (I believe during vPC convergence) forces the traffic destined from 3750-1 to 3560-1 through the STP only switch 3750-2, which apparently goes through the RSTP convergence and enables its alternate link to N7K-B before vPC has finished its convergence. After vPC convergence is finished the path through the STP-only access layer switch 3750-2 no longer exists, as vPC will take down all vPC ports and suspend orphan ports on the vPC secondary switch (N7K-A). However the MAC Address table on N7K-B still points through the 3750-2 access layer switch instead of directly through Port-Channel 12 on N7K-B and thus creates a traffic blackhole. Issuing a ping or bouncing SVI interfaces on N7K-B fixes the problem.
I ma trying to query "CISCO-PORT-CHANNEL" mib on Nexus 7000 for portChannel table and I am not getting any info.
Nexus OS versions : Nexus 7000 - System version: 5.1(5)
Nuxus 5000 - System version: 5.0(3)N1(1a)
Any pointers or other alternatives to query through MIB ?
I have been tasked to replace the existing Cat 6500 and 3750 switches by Nexus 7000 and Nexus 2000.I was told initially my boss plans to get 2 x Nexus 7000 and then eventually blow up to 4 x Nexus 7000s.For Nexus, is there a list of tasks / points that i need to consider for building the initial design?
Can i just link the Nexus 7000 like the following?
N7k-A ========= N7k-B
| |
lots of N2ks lots of N2ks
WE HAVE cISCO 2960 SWITCHES. this switch acts as a dhcp server for the hosts connected to it. Provided mac based binding to the hosts, with enabled dhcp snooping and IP source guard per interface.' I have a problem with single host couldnt get an ip from dhcp as he binded based on mac: manualip. Here is my config: We have a VLAN99, 70 hosts connected should get an ip based on mac
switch(2960<config>interface vlan99
# ip address 10.10.14.2 255.255.255.0(code)
The above host amit (10.10.14.31 swhould get this ip bindded with mac) but hez not getting manual ip i.e 10.10.14.31, but if an ip excluded from the dhcp free, he can get that ip i.e automatic ip . every other host are getting the ips as binded in the pool manual ip. Checked with
**sh mac-address table dynamic vlan 99 ()
**clear ip dhcp binding * or 10.10.14.31
** clear ip dhcp snooping binding
*** clear ip dhcp conflict *
Tried to change pool names. All these troubleshoot couldn't make me success in providing amit an manual ip.
I've got a pair of Nexus 7010's running vPC. I am having a Multicast issue with a cluster of Linux servers that need to talk Multicast for cluster/high-availability operation. All the servers need to talk to a single multicast address and I am having trouble getting them to communicate. I believe I need to enable IP IGMP Snooping Querier on the N7K's and it needs to be enabled on the VLAN where the servers reside. How to enable IP IGMP Snooping Querier on a VLAN ?
View 5 Replies View RelatedI am looking for a way to bind between a switch interface (cat 3750X) and a DHCP server reply.The switch can operate as the DHCP server .a PC connected to interface Gi 1/0/1 will lways get IP address 10.0.0.1 because it is connected to interface Gi 1/0/1, a PC connected to interface Gi 1/0/5 will lways get IP address 10.0.0.5 because it is connected to interface Gi 1/0/5 and so on... (no matter the source MAC address who sends the DHCP request).
View 8 Replies View RelatedI have a problem at a place where 5 ME3400 switches are connected in a straight line. I can't do much about the topology of that place, but the problem is they are all DHCP Snooping, but uni cast replies from the dhcp server further up the hierarchy gets eaten by the first switch! I can't really see why it not only inspects in and whines about it not being for itself - it then drops the message.
What have we done wrong (apart from the actual layout of that place, which I can't really change)?
Sep 28 13:49:29: DHCP_SNOOPING: received new DHCP packet from input interface (GigabitEthernet0/1)
Sep 28 13:49:29: DHCP_SNOOPING: process new DHCP packet, message type: DHCPOFFER, input interface: Gi0/1, MAC da: 7444.012d.debd, MAC sa: 0013.1a4a.65c7, IP da: XX.YY.186.7, IP sa: XX.YY.186.1, DHCP ciaddr: 0.0.0.0, DHCP yiaddr: XX.YY.186.7, DHCP siaddr: 0.0.0.0, DHCP giaddr: 0.0.0.0, DHCP chaddr: 7444.012d.debd
Sep 28 13:49:29: DHCP_SNOOPING: binary dump of option 82, length: 20 data:
[Code] ......
It really should just send it on, as with any uni cast not on the switch itself - it should go out Gi0/2 really. Why isn't it?
[core] -- [sw1] -- [sw2] -- [sw3] -- [sw4] -- [sw5]
All the trunks are trusted, DAI is on (I've tried shutting it off, as well), port-security is used but it's actually not dying on the switch having the client computer, but the first one in the chain with dhcp snooping.
I have a problem with high CPU load by DHCP Snooping process on Catalyst 6506 (WS-SUP720-3B, soft: s72033-ipservices_wan-mz.122-18.SXF11.bin). I have it enabled on 15 VLANS, in which there are subscriber devices residing, and sending DHCP requests through Cisco to DHCP server (Cisco acts as DHCP relay, and it's collecting the snooping database, I also use DAI).
Snooping database contains 6962 bindings now.
CPU load goes high only sometimes, and I don't have a clue, why it's going so high. It can load as high as 45-47% of CPU, like this:
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
116 81471244 322596368 252 42.95% 43.48% 36.06% 0 DHCP Snooping
When the load is high, the command: show ip dhcp snooping statistics is showing, that the overall quantity of
Packets Processed by DHCP Snooping is increasing rapidly. In normal situations, it's like 10-20 packets per second, but when the load is high, it's 1000-10000 pps.
But when I look at SPAN from my subscriber's VLANS, I don't really see any flood of DHCP requests, or something like that - everything looks as usual. Maybe, some of subscriber's devices are sending incorrect DHCP requests, that are causing packets to loop inside RP, or something like that? How can I detect that thing?
Also I thought, that if I enable the ip dhcp snooping trust mode on all of the Catalyst interfaces, the DHCP snooping will not process the subscribers DHCP packets, and I can, by exclusion of interfaces from one to one, detect, from which interface the problem is originating. But this seems to be incorrect, I turned the ip dhcsp snooping trust on all interfaces, and I still get spikes of CPU load by DHCP snooping process. Why it's still examining packets, even on trusted interfaces, is it ok?
And one more question - if I disable the ip dhcp snooping globally, will it clear all my existing bindings in snooping database?
I have attempted to implement DHCP snooping and have been having some strange issues. I have 5 3560s taht I use for my edge and when I attempt to implement on all five, the VLAN that houses my voice data appears to no longer be able to recieve DHCP lease renewals so after the 24 expiration all of my phones lose their configs. Once I roll back the changes the voice VLAN comes back. The other VLANs seem to function correctly as theya re able to renew their DHCP addresses.
The 3560s tie into each other using GIG Ports 1 & 2 and the top and bottom switches tie into our core switch, a 4507. The config that I use is below, failry simple and straightforward.
4 of the 5 switches feed our general office vlans for voice and data however the 5th switch is there for expansion and not in use. As such I have left the config changes in place on it and have tied myself and a colleague into it and have been operating fine for over a week now. So the config that I use seems sound in theory and should work on the other 4 switches with no issue.
I am working in a environment that is classed as collapssed Layer 3 environment. We have a core 6500 with routed links to 3560's which are access switches.
We have layer 3 vlans on the access switches, one for data one for voice.On the layer 3 vlans we have ip helper addresses that are used for DHCP. The DHCP servers are located on the 6500.
I recently had a incident where someone plugged a netgear router into a desk point because they thought they could use it for a switch. This router then started to dish out IP addresses to people in the morning for those who came in and docked their laptops. 99% of people weren't affected because they have desktop PC's are their leases hadn't expired.
Now we have bpduguard, bpdufilter to prevent people from plugging in switches that send out BPDU's. However this doesn't prevent the above senario where someone plugs a router or a 'dumb' switch that doesn't send BPDU's.Because of the above senario I started looking at DHCP Snooping, but I am unsure on a couple of things.
With the topology of our network I understand that I don't need to configure IP DHCP Snooping Trust on the L3 uplinks to our core switch. From what I understand I just need to enable IP DHCP Snooping globaly and then on the VLAN's on the access switch (because of the L3 topology VLAN's are local to the access switches). Only if I had L2 uplinks to the core would I need to configure IP DHCP Snooping Trust on the trunk links.
I am trying to understand the basics of DHCP snooping. I have a just a 3560 switch and a laptop ( to get a DHCP address) and my DSL router which has a DHCP server running. On the switch I have enabled "IP DHCP Snooping" and "IP DHCP Snooping VLAN 1" plugged the laptop and DSL router in and the laptop gets and IP address, should it?
I thought all ports were untrusted by default so the DHCP server should be blocked at offering IP addresses? If I wanted the DHCP server to be allowed to offer IP's I thought I should need to trust the port.
I have a new catalyst 2960,and i want to enable DHCP SNOOPING,but,it doesn't work,the server is stilling offert addresses IP and it's not connected in a trusted port,the schema is very simple:1 switch catalyst 2960 PST-S,1 server dhcp and 1 pc client,the PC and the server are in VLAN 10,DHCP SNOOPING is enabled in all ports and no port is trusted,but the client get addresse IP after retyping ipconfig /release and ipconfig /renew in dos commande.the configuration and the version of the switch are in the file attached.I tested the same configuration in a catalyst C3560-24PS and DHCP SNOOPING work normally,i tested in other catalyst 2960-PST-S,but the same probléme:DHCP SNOOPING without effect,the commands typed is:
-ip dhcp snnoping
-ip dhcp snooping vlan 10
I got some problem with enabling dhcp snooping on 4500 (cat4500e-lanbasek9-mz.122-54.SG.bin) the topology is as below: dhcp snooping enabled only on CORE (with interface trusted to dhcp server)the problem is that I put these 2 commands
ip dhcp snooping
ip dhcp snooping vlan 1
but it is not enabled on any vlan
SW-CORE#sh ip dhcp snooping
Switch DHCP snooping is enabled
DHCP snooping is configured on following VLANs:
none
DHCP snooping is operational on following VLANs:
[Code]...
On B1 if I turn it on there is a "1" in the section " DHCP snooping is configured on following VLANs:" but on core no.As you can see I did put the trusted on the interface in the direction to the dhcp.First I thought it can be a problem with option 82, I've read a lot about the issues with that, but the problem would be explicable if the client did receive IP address, but it does.
I am trying to find a command for dhcp snooping rate-limiting on a CatOS. The PFC card is PFC. PFC3B is said to support that command. But there seems no this command.
-6k> (enable) sh ver
WS-C6509-E Software, Version NmpSW: 8.4(5)
Copyright (c) 1995-2005 by Cisco Systems
NMP S/W compiled on Aug 3 2005, 13:26:46
[Code] ......
Up time is 1183 days, 1 hour, 41 minutes
I recently installed DHCP snooping on a 3750v2 switch (Version 12.2(55)SE4) and configured the uplink(Po2) as a trusted port. The problem is that clients cannot receive an IP address. When I disable DHCP snooping it is working properly. DHCP snooping is configured correctly but I don't have an idea how to resolve it. [code]I tested the solution on the same kind of hardware switch and firmware and it worked out fine. What is causing the clients not to receive an IP address from the DHCP server?
View 10 Replies View RelatedJust spoke to the TAC and didn't get the information needed. When configuring ip dhcp snooping database I am adding this to my configuration:ip dhcp snooping database scp://dhcpsec@192.168.1.50/home/dhcpsec/switch1.dhcp.database.txt..I assumed that to do this I would either specify the password on the command line, similar to the way its done when using ftp/http, or that I would need to create a public/private key.I have enabled scp and can manually copy a file from the switch to the linux server. So I believe I have all the aaa commands correct. Cisco WS-C3560G-24PS System image file is "flash:/c3560-ipservicesk9-mz.122-55.SE.bin".
View 3 Replies View Relateddoes Cisco 2600 series switch support 802.1x and DHCP snooping?
View 6 Replies View Relatedi have a strange problem in my campus network.im trying to run port security on my access switches which they are 3550 with ios c3550-ipservicesk9-mz.122-52.SE when i run the port security with Sticky option, even i put 1000 mac address for just learning on the port but when i issue the switchport port-security command every pc connected to that port loses its connection with network UNTIL i enable dhcp snooping!!! all my client are getting they ip address from DHCP server but strange thing is that how on earth i have to enable DHCP snooping to port security work properly? also when i check the configuration under the interface when dhcp snooping is not yet enabled switch doesnt add any mac address under the interface so no one can work until i enable snooping and then switch adds mac addresses under the interface configuration.is this Bug on this version of IOS?[code]
View 4 Replies View Relatedwe've an infrastructure were the Access is based on Cat3750G Stacks connected to both Cores using L3 connections.On the Access Switches are implemented the following features DHCP Snooping, IP Source Guard and Dynamic ARP Inspection and all is working fine since years...the DHCP Servers are on a dedicated stack which act as a SFarm.
On the Access Switches the port configuration is the following:the Uplink Ports to both of the Cores are configured in TRUST for DHCP Snooping and ARP Inspection the Access Ports, where the end-device are connected, are UNTRUST for DHCP and ARP Inspection with IP Source Guard Active Right now I've to add a new L2 switch on one of the Access Port and I'm wondering if this is possible since I've to keep on the Stack Access Ports all the security feature active and I've also to implement DHCP Snooping on the new L2 switch to avoid rouge DHCP Server...
I suppose that the uplink to the L2 switch on the Stack Access Switch should be left as it is connected to an end device...but the uplink port on the L2 switch should be set up as TRUST...isn'it? Keeping in mind that I want to implement DHCP Snooping also on this L2 switch to avoid that Rogue DHCP Servers will impact the end-device connected to this L2 switch...is this scenario possible??? or I can't do that and should leave DHCP Snooping only on the Access Stack.
I have a problem with DHCP. I have two 2960 connected with a port channel on ports 47 and 48 as trunk with native vlan 10. I only have this one vlan. In port 1 of sw 1, I have a C800 as DHCP server.
I have an AP autonomous with single ssid on vlan 10. When I connect the AP to sw1, I receive dhcp with no problems.When I connect the AP to sw 2, I’m not getting IP by DHCP.I have DHCP snooping working on vlan 10 on both devices.
The ports where I connect the AP are access ports on vlan 10 config as trusted.The trunk ports are also configured as trusted.The port 1 of ws 1 that goes to the C800 is also configured as trusted.
figure out why I’m not getting IP by DHCP when I connect the AP to the SW 2.The only I notice is that when I connect the AP to sw 2, I get on SW 1 the message of packet drop by option 82, but even after configuring ip dhcp snooping information option allow-untrusted on both switches, the problem persists.
Should I install any special license to enable vrf within Nexus 7000 VDC? I observed that vrf routing instance is not enabled in the VDC.
View 2 Replies View RelatedI am configuring NTP on a new Cisco Nexus 7000 running version 6.1(2). NTP is working properly between the access switches and Nexus, however when configuring Authentication, NTP is not working anymore.
confguration:
Nexus 7K server
=============
ntp server x.x.x.x
ntp peer q.q.q.q
ntp server e.e.e.e
ntp server r.r.r.r
ntp source-interface Vlanx
[code]...
why NTP authentication is not working !!!!! on Nexus 7000
On a 7K (5.0(2)), I have a situation where the FIB and RIB are out of sync. I'm not sure it's causing a problem, but it's been implicated in some weird packet loss issues. It seems like it could cause network issues if you had two routes in the RIB, only one in the FIB, and then you lost the single path in the FIB. How the RIB/FIB gets out of sequence, how to proactively know about it (nothing in the logs here), and whether or not this is a big deal or a red herring?
Here's sample output that illustrates the RIB and FIB being out of sequence.
ROUTER1# show ip route 172.16.100.1
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
[Code].....
We have a DHCP SERVER implemented in a cisco router 2610.This router is connected to a switch cisco 2960 configured as DHCP SNOOPING. At the switch appear the next log message: [code] The ip address: 10.100.200.1 belongs to DHCP SERVER configured at router cisco 2610. What to do so these log messages does not appear any more? Do I need to do some configuration changes at some switch or router?
View 11 Replies View RelatedWe recently purchased a pair of 2232TM Fabric eXtenders just to find out that our Nexus 7000 does not support it. Will there be support for the 2232TM FeX in Nexus 7000 any time soon?
View 4 Replies View RelatedI have two data centres connected via a L2 DWDM, my manager wants to look into using OTV to get rid of the layer 2 broadcasting issues.
Problem is the DWDM is 1000BaseSX, which is only supported on the N7K-F132XP-15. (and the N7K-M148GS-11 but that doesn't support FCOE, so many bloody caveats). From what I can gather OTV is not supported on the N7K-F132XP-15.
Is it possible to terminate the DWDM on the F1 card & loop another port from the F1 to a port on the N7K-M148GT-11 & run OTV on the M1????
Either using VDCs or just an isolated VLAN on the F1. Is there any better way to do this? Hardware has not yet been purchased.
I am seeing an issue that after deleting/recreating one of the VDC in Nexus 7K, VLAN is not been able to be configured within the VDC although it is not actually a reserved VLAN. Could it be anything missing in the license installation? the version of the image is NX-OS 6.1.2
StorageVDC(config)# vlan 100
^
invalid vlans (reserved values) at '^' marker.
We setup two n7K as core switches in our network. We configure VPc peer link as well successfully. We are using mgmt interface of supervisors as a peer keep alive interface, so what happen when this keep alive gets down? Are we loss Vpc peer link between both nexus 7 K?
View 4 Replies View RelatedI have a pair of Nexus 7K's running 5.1(3). I have a handful of edge devices that I need to mark ingress traffic, and need to mark both DSCP and CoS. Right now, I have a working config that marks DSCP appropriately.While that works dor DSCP, the MQC will not allow me to mark both DSCP and COS in the same class, and unlike IOS, it appears that Nexus does not have a default DSCP-to-COS mapping. My understanding is this can be solved using table maps, but I don't see how that can solve my problem in this specific scenario (it appears I can do marking or table-map mutation, but not both?). How I can accomplish both?
View 5 Replies View RelatedI cannot get the AAA tacacs+ authentication to work on my Nexus 7000.
View 4 Replies View RelatedI need to know how is the ambient temperature for the Nexus 7000 switches to plan a new datacenter. In the datasheet I found the following information regarding this topic:"GR-63-CORE Network Equipment Building Standards (NEBS) specification published by Telcordia Technologies in Section 4.1.2". How are the specification for temperature in this standard?
View 1 Replies View Relatedregarding QOS on Nexus 7000. Our Nexus 7000's form a collapsed distribution/core layer, our access layer switches are are a mixture of Cisco 3750 & Cisco 4507. 3750 switches will connect to Nexus switches via 1Gb uplink, 4507 switches will connect via 10Gb uplinks. Each Nexus will be connected via 20Gb port channel, all servers connect to the Nexus switches via 1Gb links. We're implementing a new telephone system soon which will be using VOIP so I need to configure the switches to perform QOS. The IP phones will mark the RTP traffic with DSCP value EF and call signaling traffic CS3. I'm fine configuring qos on the access layer switches, its just the Nexus switches which I'm not sure about.
Do I actually need to configure any QOS parameters on the Nexus switches so they will prioritise the VOIP traffic. If my understanding the Nexus switches will trust the DSCP values and assign the traffic to the relevent queues?
Just for information VOIP is the only traffic I will be marking QOS values