I've been looking for a way to detect the level of traffic caused by unknown unicast traffic on a Catalyst 6509.I have found mechanisms to mitigate it but nothing to actually detect/measure what the levels might be.
View 3 RepliesI have a serious problem with nexus 7018, there're unicast flooding on one n7k, named n7k-1, which is the member of vPC domain combined with 2 N7Ks. [code]I had clean the mac-address-table, and all mac-address-tables had been synced fine, and the unicast flooding went away.
How could I fix the mac-address sync function between the modules ?
I'm having an issue with my network, where we're are experiencing random and brief network outages. They happen a couple times a day and last 5-10 seconds. when I check my two backbone switches (4506 : Supervisor: WS-X4516-10GE ,IOS : cat4500-ipbase-mz.122-31.SGA8.bin), STP remains normal and no topology change occurs.
View 16 Replies View RelatedThe below output has taken from Cisco 3750 switch which the CPU utilization is more than 80%. What is the meaning of this below information.
switch#debug platform CPU-queues icmp-q
debug platform CPU-queue icmp-q debugging is on
Feb 6 18:44:09.860: ICMP-Q:Dropped redirect disabled on L3 IF: Local Port Fwding L3If:Vlan41 L2If:GigabitEthernet1/0/8 DI:0xB4, LT:7, Vlan:41 SrcGPN:8, SrcGID:8, ACLLogIdx:0x0, MacDA:0019.aade.0d58, MacSA: b8ac.6f2a.2734 IP_SA:10.43.41.87 IP_DA:172.20.31.25 IP_Proto:6
TPFFD:ED580008_00290029_00B0009F-000000B4_90BD001F_6C6E1FC0
I have a Canon ScanFront 220 network scanner that seems to have a problem with our network. It's plugged into a Cisco 3560. The network is operational, just chatty.
A wireshark session for just a few seconds looks like this: (192.168.81.42 is the scanner)
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.89 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.90 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.91 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.92 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.93 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.94 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.95 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.96 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.97 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.98 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.99 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.101 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.102 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.103 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.104 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.106 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.108 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.109 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.110 Vlan81
1w4d: IP ARP: rcvd req src 192.168.81.42 0000.8583.2c43, dst 192.168.81.111 Vlan81
I can't find anything on the scanner that would cause this.
I have a Nexus 3064 which is not recording source MAC addresses after a successful ARP. The switch is then flooding the entire vlan with unicast traffic.
The config is a boring single VLAN. One port (48) is going to a 6509. Not as a trunk, just extending the VLAN. There are SVI's on both switches. the default route for the Nexus users is the 6509's IP.The switch was basically, pulled out of the box, setup a single vlan(with jumbo frames) andan SVI, then plugged in the users. Nothing special.
My IPTV connection works fine so far but as soon as I start watching TV I can't use my WiFi connection anymore. My router is an "Alice Modem 1121" (SIEMENS S1621-Z220-A) with 4 LAN ports and a WiFi interface (4th LAN port provides the IPTV). It is directly connected by wire to my PC's ethernet card for the IPTV and the internet is provided via the WiFi. When I activate the LAN connection the WiFi and internet connction stays up and requests can be sent but nothing returns anymore. Another device (iPod) has no problems with accessing the internet while IPTV is in use. I also have a Netgear WNR1000v3 router which I tried to use as AP instead but it's exactly the same problem. Unlucky the Netgear router is not supported to use dd-wrt firmware yet (I've found a step by step guide to prevent multicast floods with dd-wrt/ebtables). But maybe the Alice Modem can handle this problem on its own. I read some stuff about VLANs and splitting them but I have no clue how that would look like.
The "nas_0_1_34" is for the IPTV.
I am planning to get the unicast streams from different 2-3 sources over internet, and I am doing NAT for port-forwarding all those unicast streams to a one private IP. Attached is the setup for your understanding.Setup: - Both unicast streams will be hitting to One Public IP (3.3.3.2) on UDP/TCP Port 1234, 1236 & 1238 only & the same ports need to be forwarded to natted One Private IP (10.10.10.4)
1)NATTING these 2 unicast streams into one private IP(10.10.10.4) by checking Source & Destination based IPs and ports, but in below configuration I cannot achieve on checking Source & Destination based IPs and ports
Router configuration:-
interface GigabitEthernet0/0
description ***Connected to Internet ***
ip address 3.3.3.2 255.255.255.252
no ip redirects
no ip unreachables
[code]...
We recently acquire a cisco 2921/K9 router to interface 2 networks
Network 1 : 169.254.XXX.XXX/16 on GigabitEthernet0/0 interface
Network 2 : 192.168.1.XXX/24 on GigabitEthernet0/1 interface
On the network 1 side there is a multicast source (169.254.200.200 destination : 225.0.0.1) on the network 2 side there is 1 receiver which is not multicast capable(old) but i want it to receive the multicast stream for the moment we configure the ip multicast-routing and each interface each interface with ip pim sparse-dense-mode then configure the GigabitEthernet0/1 in order to join the multicast group (using ip igmp static-group 225.0.0.1) and wireshark confirm that the multicast stream on the network 2 side from 169.254.200.200 -> 225.0.0.1 of course the receiver don't the stream, but if i force a "multicast to unicast" process inside the router it shall be ok.. after many hour of internet browsing i found 2 solution :
- NAT, [URL]
- multicast service reflection (Cisco documentation)
The NAT example don't work ,what is the best way to do this task.
We have a problem with NLB on a SG500-28P which is a major issue for us.
I am investigating a problem together with Microsoft Support about a download/upload performance issue with a Microsoft Forefront TMG array which is connected to a single SG300-28P. Àpparently this issue exist on every NLB array we implement. I am now at the point we asume the SG500-28P does not handle NLB in unicast mode very well.
We have a network topology as shown below:Please note the actual public IP Addresses are hidden and the internal IP Addresses are diffrent, for security reasons.
Our SG500-28P is configure in L3 mode. It hosts three subnets you see above. The two TMG servers are configured with NLB (in unicast mode) on the Internal Network and External Network interface. It is connected to the internet and our internal network. These TMG Servers are in fact Edge Servers. Our other servers and client are in a different VLAN. The default gateway flows through this NLB Cluster [10.250.0.254].
Problem: When a client uses its default to connect to the internet the performance is very and very slow. With an internet connection of 10/10 we get 10/2. With an internet connection 100/100 we only get 7/1!.
Now we have tried everyting we can imagine. I can't write down all, because that would be a lot. One thing is worth notice; When we move the client to the same VLAN as the NLB Cluster and the client uses 10.250.0.1 as its default gateway, the problem still exists. But... when the client uses 10.250.0.254 as its default gateway the performance is outstanding 95/95! Apparently if traffic for the NLB Cluster is routed through the SG300-28P the performance drops like a rock.
I have never seen this before with SG300 series switches, although this environment is different. Normally I would configure NLB in multicast mode. But the switch does not allow to add static ARP entries for multicast MAC Addresses.I know NLB in unicast mode introduces switch flooding and such. But why does the SG500 not handle this right? Is there anything I can do about it?
I was wondering if the following scenario would work:
2 Microsoft TMG servers (could be any W2K8 R2 based server, e.g. UAG, Exchange etc.) configured for Unicast NLB. The servers are connected to separate L2 switches which are connected to a highly available central L3 switch (see attached drawing).
Unicast NLB works in such a way that it uses a shared virtual IP and a virtual MAC addres which is not used as Source MAC address when the TMG servers are respondign to requests.Basically it relies onto the fact that the switch does not learn the virtual MAC address and floods all packets destined to the virtual MAC on all ports. The L3 switch would learn the MAC through ARP. The question now is, what the L3 switch would do, if it receives a packet destined for the NLB VIP. It should do an ARP request in order to receive the virtual MAC. How would he decide on which port(s) to forward the packet as he does not know on which port the MAC is found. Can he make a decision based on Layer 3 (IP/VLAN based) therefore he knows that the VLAN for the TMGs is connected on those two uplink ports?
I have a 2x Cisco 3750G switches (Stacked) that are part of an IP Video Surveillance System .All network is set to 1 VLAN (VLAN 1 default).The Cisco SWs ( Core ) are configured with IGMP Querier + Snooping .Connected to the Cisco SWs are 4 Fiber Rings(Loops) for redundancy . RSTP and IGMP Snooping are enabled on all the network SWs .Network Architecture Figure :
When all Fiber Rings (Loops ) are connected , the Cisco and Ring SWs spanning-tree tables show the blocked and forwarding ports properly .I am able to connect all my IP Cams + Encoders to the Ring SWs and connect my Servers + WorkStations to the Cisco SWs to record and view the multicast ip streams .All streams from Rings 1 ,3 and 4 are getting normally to the Servers + WorkStations through multicast ( IGMP Snooping are filled correctly on the Cisco and non-Cisco SWs ) . All multicast streams are joined normally except for Ring 2 .The Multicast streams passing through Ring 2 will operate normally for around 2 hours then after that the Fiber SWs begin to flood their multicast traffic causing the cams on the same switch to drop off the network .
I checked the Configuration of all the SWs on Ring 2 but all are are the same .
What is weird is that I have to set all the streams to unicast to stop the flooding just on Ring 2 (All other rings are not affected ) then after some time if I enabled a video multicast stream on one of the SWs of the Ring it will be streamed properly to the Servers + WorkStations ( All IGMP tables along the way will be filled properly ) then again after 2 hours or so , the flooding will start again suddenly and all IGMP table entries for the SW on Ring2 will be empty . No problem occurs on the other Rings which have more multicast streams .
We have problems with 3 switches in our network.
Users continues receive adresse via DHCP, but no traffic was forwarded. After reboot switch works fine about one week and problem arrives.
I telnet to one problem switch and try to found reason by reaply acl and source guard and saw some strange message:
nov-20(config)#int r gi1-48
nov-20(config-if-range)#no service-acl input
nov-20(config-if-range)#service-acl input 2
Exceeded the maximum ACE allowed in the system. -repeated 48 times
Configuration and log int attachment (show tech-support)
port 52 - uplink, 1-47 - users, 49-51 - downlink switches (SPS224g4) with aprox 200 pc connected. 48-ups
i recently identified all switch ports in my network on 6509 core were Transmitting Mail server Exchange traffic that was destined for Unicast NLB cluster. and it was impacting various HOST machines NIC cards/performance.After reading this article, i moved NLB CAS servers behind a dedicated cisco Switch.
[URL]
Now My core switch can learn mac address across its trunk port where CAS servers are connected on dedicated switch. but still i can see traffic Transmitting out to my all switch ports of same VLAN ( same as NLB VLAN).
There is a unicast flood on 3750 killing slow modem links. How to determine source MAC address of flooder? Is there a rate limit feature for it?
I know how to block it completely on port-level, but it breaks normal network operation. (when port goes down for some reason, it's learned MACs got flushed and since other hosts know MACs, they keep flooding untill their arp caches expire).
Is it possible to convert multicast streams (224.0.0.1:1234) to unicast (Receiver 10.0.0.1:1234) at the router level.
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The big problem is i don't know what wireless card it is and its hard to find out because the support pdf for the laptop shows multiple possible cards.
[URL]
serial modem US robatics 5686G is not detected on windows server on serial port com1. i tried to restart the server . turn the modem on and off disable the com1 port reenable it again . update the firmware of modem on different workstation and connect it back to server ( couse it's working on another workstation so it's not the modem) i really don't know what to do is there a trick for this like in registry or somthing in mouse settings that mouse could actully detected on com1 and don't let the modem to show up on device manager? by the way modem cable is serial cable i tried to change the cable as well non of my ways works?
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