I have a 3945 with a basic DHCP configuration applied to it. This 3945 is connected into one of the access ports of my nexus switch. I'd like to simply have the 3945 hand ip addresses out to other clients connected to the nexus switch. I have zero experience with nexus & haven't been able to turn much up through searching the net.
I have a Cisco 2951 Router and I am trying to set it up to use DHCP and for security purposes I need to use the "IP Access-Group in" command. The DHCP will not work when I have this command on the interface that I need to run it through, DHCP works fine when I do not have the "IP Access-Group in" command in the configuration. When I check the log after the failed DHCP attempt it shows up as denied, as if it's being blocked. The IOS I have is c2951-UNIVERSALK9-m 15.0 (1) M3. Conf Reg 0x2102.
We have 2 nexus 7010 switches configured with HSRP in the network. For all the vlans core1 is Master and Core2 is standby. In the current setup we have external dhcp server and dhcp relay is configured for all the vlans on Master and standby switch. The setup is running the IOS 5.2
Activity Done: During the Maintainacne activity, we isolated core1 switch in the network by disabling the vpc/keepalive and all the uplinks from access switch. The core2 switch was master for all the vlans.
Issue observed: It has been observed that new users were not getting ip address from the dhcp server. The ethereal capture showed that dhcp server was not getting the dhcp requests from the core2 switch. We disabled the dhcp feature in core2 and enabled again with dhcp relay again configured on vlan interfaces .even after doing this no change was observed in behaviour. Finally we got core1 back in network by enabling all the links.
Observation: The moment VPC link came up between the core switches, users started getting ip's from dhcp. Then we started enabling all the uplinks on core1.Core1 again become master for all the vlans and users continued getting ip’s. Network running fine.
Further Testing
1. For one of the vlan, core 2 switch has been made primary and for new users checked the dhcp functionality and it was working fine. The aim was to identify if anything wrong on core 2 related to dhcp relay
2.Again we changed the priority for this vlan and made core1 master for the same. This time we disabled this vlan on core1 and tried new user with core 2 became master and dhcp functionality worked fine for new user. Actually in this case we have simulated the same behaviour when we observed the issue with only difference of VPC was not available during the issue time as core 1 was isolated form network Inputs needed.
Is there any known behaviour for dhcp functionality when VPC is unavailable? If we see the test scenario2 (wherein core1 was master for the vlan and we disable this vlan on core 1 and core 2 was able to relay dhcp requests for new users in this vlan.) it was actually same as scenario we observed during issue time..
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).
We are facing issue of continous packet discards On nexus4001L link (int po2) to Nexus5020 switch. Nexus4001L is installed in IBM blade center server and we have FCOE enabled in this setup. [code]
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 are planning a Nexus datacenter project with this layout:Our experiences with Nexus switches are not so large until now and the manuals are very extensive.Both N5K´s should be connected directly with all 4 N2K switches. I did not find a layout like this in the manuals. Only a design,where only 2 N2K are connected to one N5K, with this fex config:Now I´m not sure if it is right to make a config like this with the same slots and fex´s or with different slots and fex´s.
I recently saw it for a good price online, and required a new router (had a netgear that died, and my backup was a really buggy Belkin which I'm currently using).I'm having an issue with the internet, in that when I connect my ADSL modem to the WAN port it seems to work fine, however the PC can't connect to the internet. When I go into the settings it says that the WAN connection is OK and even shows my external IP. I have it set via the stardard DHCP setup.Should I have done anything specific to my ADSL modem before plugging it into the RV180W? The Modem (D-Link 320B) also has a DHCP server on it, however I assume that this causes no issues when connected to the RV180W.
I have 2821 router configured with two subinterfaces. This router is connected on cisco 2960 switch. The trunk on 2960 is configured without any prunning of vlans. I noticed that udp broadcast traffic is being forwarded through my router on native vlan 1 (this interaface do not have ip address configured). Below is configuration:
Router:
interface GigabitEthernet0/0 no ip address duplex auto
I'm working with some 891W's that have the internal 800-series AP. I have this router set up initially using Cisco Config Express, then, using Cisco Config Professional 2.5 I set up the firewall and other featuress that CCE doesn't do. Overall this is a very simple router, meant to be a small business Internet gateway device but is currently in my lab.
The intended WLAN setup is very simple. One SSID, with broadcast enabled, using WPA2-Personal. Auth: open Encryption is both TKIP and AES-CCM.
However no matter what I do I cannot get thhis thing to broadcast . In the past I had sometimes run into issues where if I had more than one AP running independently it would cause a channel conflict and one or both would cancel each other's radio, so I disabled all other AP's in my vicinity.
Also I've had issues in the past where f I enabled both TKIP and AES, sometimes clients can't find the AP as a result. My solution had been to disable one of them leaving just the other - no change here however.
Via the IOS, ssid config shows mbssid guest-mode which I believce is default.
Interestingly, if I do the following:
ap# Config t ap(config)# dot11 ssid <myssid> ap(config - ssid)#guest-mode end
I end up with both "guest-mode" and "mbssid guest-mode" in the sh run for the AP, and voila, my AP broadcasts the SSID. However clients end up joining without any security at all, no prompts for pre-shared key or anything.
I am using 3560.IP rouitng is being turned off on this.Curious to know if I will create etherchannel or port channel.I think etherchannel.Correct me if I am wrong.On connecting switches I have vlan10,20,30 to be allowed.I am sure I need to allow these all vlan in 10,20,30 which are on the trunk port on each side switch.Post that will add channel-port lacp and make it in active mode.Is that correct.This way traffic will be load-balanced/aggregated on minimum 2 ports who are the part of this.
how to configure the ASA 5500 with "Directed Broadcast" for Wake of lan from other networksegment. we want pass traffic from 192.168.10.0 network to 192.168.100.0 DMZ Network to turn on the server with Wake on Lan.
I read something about "Static NAT" but how do i make this one?
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.
I recently bought SG-300 28P to create the VLAN. My network hs 3 subnet 192.168.1.0, 192.168.2.0 and 192.168.3.0.My main net work is 192.168.1.0. I want to divide it to VLAN to eliminate the boardcast storm; especially from the domain 192.168.3.0
But I want all the devices from 192.168.1.0 to access other subnet.
We have 2 switches split across 2 datacentres connected via an interconnect. Over the past couple of days the interconnect provider's Cisco kit has shut down our port (err-disabled) due to a broadcast storm. They had the level set at 1 which I thought was a bit low. They say they tried to set to 2, then 5 but still kept tripping the storm-control feature so they set at 10. They say they've always had it set at 1% (on a 100Mb switch) and so we must be generating more broadcast traffic.
I'm trying to identify where the broadcast traffic is coming from. On our Cisco 3750 I've clear interface counters and when I do a sh run | i broadcasts there are a few ports which have what seems like a high broadcast count. The one port that is especially high and the only one tripping the storm-control feature (I've enabled on all our ports to try to identify where the traffic is coming from) is the port connected to the 100Mb interconnect. I've mirrored that port to another port and connected a server with wireshark so I can capture all the traffic across that port.
What I'm struggling to find is the source of the broadcast traffic.I have a few questions are these broadcasts layer 3 or layer 2 broadcasts. Also in the output below when it says broadcasts received is this inbound to the port i.e. from the connected device or is this a total of inbound and outbound broadcasts.
When I use wireshark and filter the capture on broadcasts (ff:ff:ff:ff:ff:ff) I see only 200-300 compared to the thousands the switch is reporting.If I filter on the broadcast IP address I also don't see the numbers corresponding to what I see in the show interface output.
GigabitEthernet1/0/1 is up, line protocol is up (connected) Hardware is Gigabit Ethernet, address is 0014.a93f.7401 (bia 0014.a93f.7401) Description: Interconnect MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, reliability 255/255, txload 4/255, rxload 44/255 Encapsulation ARPA, loopback not set
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also I'm currently doing : monitor session 1 source int g1/0/1 both, and also tried just rx incase I just need to be looking at receive traffic but still nothing is standing out.
i bought a cisco 2950 series switch to play around with and im trying to set it up to SSH. I have google'd a bit on how to do this and i've sort of hit a wall... i have downloaded the cryptographic image from cisco's website, installed a TFTP server (think this is where my issue lies) but when i do the copy tftp flash global command i keep getting the error accessing "xxxx" message.I have tried allowing the server through windows firewall, disabling windows firewall, allowing access through the router..
How do I limit broadcast/mulitcast traffic on a switchport to e.g. 5000 pps ? I don't want the port to shut down, just block or drop broadcast traffic that exceeds 5000 pps.
I have a bunch of 3750x switches that each have a 10 gig routed link back to a central 4507 (loopback = 172.30.255.255).We carved up a /24 (of course, the /24 doesn't really exist except in our address tracking spreadsheet) into a bunch of /30's for routed WAN links and /32's for loopback addresses.We started on the low end for /30 subnets (ie 172.30.255.0/30, 172.30.255.4/30, etc.).We started at the high end for the /32 loopbacks (ie 172.30.255.255/32, 172.30.255.254/32, etc.)
Well, when I try pinging 172.30.255.255 from the access layer 3750x switches, the 3750x seems to be treating it as a broadcast ping where it lists each member that responds instead of the regular !!!!! response (this makes think something is odd with the 3750x). Of course, only one member responds (the core). But even the core seems to respond with the other end of the /30 instead of the actual /32 loopback (which makes me think something is odd in the core). I could have sworn that I've setup similar topologies without problems (ie, using 10.0.0.0/32, 10.255.255.255/32, etc as loopbacks) and as long as the mask is a /32, it should work.Also, I can ping/ssh to that loopback if my laptop is on a directly connected subnet. But I can't do it from any of the 3750x switches (which are also directly connected).I've double checked for overlapping subnets, but nope. I don't see any. Routing looks fine. The actual /32 is being propagated everywhere properly.
We run a network of several 2960G and 3650G switches in a network with a number of VLANs. One one particular VLAN (let's call it VLAN 10) it appears that non-broadcast traffic (i.e. normal unicast traffic) is being copied to every port in VLAN 10 only on one switch . The traffic is not crossing trunk ports and does not appear on other switches that have ports in VLAN 10. We first spotted this by noticing that a UPS port had an unusual amount of activity on our port througput graphs:
This traffic at 4 am is not expected and this profile is repeated across all ports in VLAN 10 on this switch (a WS-C2960S-48TD-L stack running IOS 15.0(1)SE3)\iffed one port using local SPAN (the UPS port) and discovered that this traffic was not broadcast, which was running at a normal low rate at all times. The traffic appeared to be unicast traffic from other ports of the sort you might see on a hub. It was from various hosts that live on VLAN 10, most (not all) of the conversations had one end station homed on the 'problem' switch. There are about 800 non-broadcast packets per hour and this is a busy VLAN so it does not account for all the traffic on the VLAN.
I have recently configured secondary ip address on LAN Interface of Cisco C6509.. We have some application which needs to use broadcast traffic communication to communicate with client... Broadcast is working within subnet & also working from broadcast server to primary subnet. But not working from secondary subnet.. I have checked broadcast within secondary IP range & it's working fine... Secondary not working broadcast with primary and also with broadcast server... broadcast address is different for these subnet but both should be communicate since configured on same interface... When I went through Cisco website found that command "ip directed broadcast" which will pass broadcast to different subnet... But I'm not sure whether any other impact if I enable that command on particular Ethernet interface...
Our network feels slow and trying to find the best way to investigate this properly. We have Cisco chassis 4500 with mix of 3560/2950 Edge switches 1GB backbones and WLC/WCS in place. The network is broken into multiple V LANS and IOS on our switches haven't been updated in 3-4 years.
On a wireless laptop (G) with get throughput of 1-2MB/s transfer speed with usually 10 clients per AP and LAN we get anywhere between 7-15 MB/s transfer. Using wire shark on a wireless laptop we see a lot broadcast traffic from other clients and the same for LAN. What is the best way to troubleshoot performance issues on the network and where do I start?
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:
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?
I have two AC1200 routers? how do i connect one ac1200 to another ac1200. Only one should act as a DHCP server and broadcast wireless; the other should be simply just a hub (vs. me having to buy a separate hub). What are the correct settings and connections?
Does the nexus 7010 support virtual switching yet? All of the posts I have found from about a year ago say that it is going to be supported, but there were no dates listed. I heard the same thing from Cisco a while back, but haven't followed up with it.If it is supported finally are there any configuration guides available for it?
Lucien is a customer support engineer at the Cisco Technical Assistance Center. He currently works in the data center switching team supporting customers on the Cisco Nexus 5000 and 2000. He was previously a technical leader within the network management team. Lucien holds a bachelor's degree in general engineering and a master's degree in computer science from Ecole des Mines d'Ales. He also holds the following certifications: CCIE #19945 in Routing and Switching, CCDP, DCNIS, and VCP #66183