Cisco Switching/Routing :: 3750 - Blocking Selected ARP Broadcasts From Particular Trunk Port Via DAI
May 17, 2012
We had a core switch (Cisco 4503), distribution switches(Cisco 3750) and access switches in our network and consists of many vlans. Almost all vlans uses DHCP Pools. But for few vlans DHCP is not yet configured due to initial design poblems. Recently one of the rogue user in vlan 1 connected to one of the access switch send rogue arp packets to the network (suspecting arp packet with interface vlan 1 ip of core switch with wrong mac-address (gateway ip of vlan 1)) and resulted in a prolonged network outage for the vlan 1. Any way we are going to seggregate vlan 1 into different vlans, but before that we need a temporary plan to block such kinds of attack like enabling DAI in the switch. I have checked the DAI implemenation feasibility with my knowledge and found that it is not possible to configure to the access switches(Cisco 2960) in which the user directly connected. But found that Distribution switch connected to that particular access switch seems to be able to configure since DAI commands are available to configure in switch.
Is it possible to block ARP packets with the interface vlan 1 IP Address with rogue mac-address by configuring DAI in the above mentioned Distribution switch and the port connected to the mentioned access switch?
View 2 Replies
ADVERTISEMENT
Oct 3, 2012
Is it possible to rate limit on a L2 trunk port on a 3750?
current port config and ios are as follows;
interface GigabitEthernet1/0/50
description *** Connection to Fiber Link ***
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,172
switchport mode trunk
end
flash:c3750-advipservicesk9-mz.122-46.SE.bin
i was wondering if the "srr-queue bandwidth limit 10" command would work to limit the output from this interface to be 10 % of the port bandwidth and then the same command could be done on the other side.
View 1 Replies
View Related
Feb 18, 2013
I have a 3750g connected to a "core" switch stack of 7 other 3750g's via 2 GigE ports in a trunk. This is currently in a switchport mode access port- channel so only the default vlan data is sent over. Now we have a need due to physical location of these switches, to allow vlan20 (DMZ) from this 3750g to the switch stack. I will configure a few ports on the switch stack for vlan20 and they need to be able to talk to the stand alone 3750g.To do this I will change the port channel on both endpoints to
-switchport trunk ecapsulation dot1q
-switchport mode dynamic desirable
also making the appropriate change on the interfaces belonging to this trunk.My question is, now that its a trunk port that carries multiple VLANs, how much is the bandwidth reduced on that 2gbps link?I have a very active VLAN (10) on the stand alone switch, but on the core I'm not going to be assigning VLAN 10 to any ports. So does traffic from VLAN10 even come across the trunk (wasting bandwidth) if no ports on the core side are assigned to it? I really just need vlan 1 and 20 (for now).
View 11 Replies
View Related
Sep 26, 2012
Cisco 4506-E port configuration
WESTERN-4506-01#show int g4/47
GigabitEthernet4/47 is down, line protocol is down (notconnect)
Hardware is Gigabit Ethernet Port, address is 0022.554c.01fe (
fe)
Description: Trunk to 425
[code]....
Cisco 3750 Configuration
interface FastEthernet1/0/1description 425Linkswitchport trunk encapsulation dot1qswitchport trunk native vlan 30switchport trunk allowed vlan 30,35switchport mode trunkswitchport nonegotiateswitchport port-security aging time 2switchport port-security violation restrictswitchport port-security aging type inactivitystorm-control broadcast level pps 300storm-control multicast level pps 300storm-control action trapmacro description cisco-desktopmac access-group AuthorizedHosts in
I have mac address' populated. I can see the device in layout on CNA with the proper name however cannot ping it.
4506 is 10.30.30.1
3750 is 10.30.30.2
View 10 Replies
View Related
Nov 8, 2011
I have a couple 3750 switches that I am trying to run VTP Version 3 on.one as primary and the other as "server" which implies secondary from my research. [code]Additionally, running a show VTP devices yields a "No VTP3 devices found" on both devices. Despite ensuring that the domainname and password match.I have a patch cable from Gi1/0/1 on switch one runnning to Gi1/0/1 which from what I read is acceptable on GigE.
View 2 Replies
View Related
Jan 29, 2012
I have client who has two distant offices with 3750 L3 as core (do all vlan routing for local office) and multiple L2 access switches with multiple VLAN’s connected to it. First 3750 is hub also connected to internet, second 3750 is spoke and acting as a router on stick. We have eigrp configured on both side ISP provided client 100Mbps link as a trunk with two vlan; vlan10 for voice and vlan20 for data. We assigned two small subnets to these vlans 10.15.17.0/29 and 10.15.17.9/29. Hub addresses are 10.15.17.1 and 10.15.17.9 respectively. How to force voice over VLAN10 and data via vlan20, but still do some load balancing? How to setup default route on second (router on stick) switch?
View 1 Replies
View Related
Nov 8, 2011
Currently we have a 6513 core (running IOS and doing limited routing) with VLAN Trunking to about a dozen 3560 edge switches, with various VLANs going to each of the edge switches. All works well. We are downsizing and replacing the 6513 core with a 3750G stack. We have the stack up and running in the lab, and want to slowly (as we move floors) migrate all of the edge switching to the 3750 stack.
The plan is to connect the 3750 stack to the 6513, then slowly migrate the edge switches to the stack (from the 6513). I would like to put in place 4 x 1GB trunk links between the 6513 and the 3750 stack before I start moving edge switches to ensure adequate bandwidth. Once all of the edge switches are on the new 3750 stack, I will start to decommission the 6513.
What is the best way to configure the links between the cores (old 6513 and new 3750 stack)? I can easily get the edge switches configured to the 3750, but am worried about the core links. I really want to avoid having to perform an all-at-once cutover of the cores. Another question is when do I try and migrate the VTP server role from the 6513 to the 3750 stack? I could simply make everything transparent, and ditch server-based VTP, as we rarely change or creat VLANs.
View 3 Replies
View Related
Mar 18, 2013
I am taking only undersize errors on catalyst 3750 trunk interface (attached some outputs)...the other end is a 4500 switch and the interface is clean..can this be related to any bug ? this is my root port and often leading to trouble sometimes STP BPDUs transportation are affected..
View 4 Replies
View Related
Nov 13, 2012
I have a 3750 as a core and have a series of HP Procurve switches that are daisy chained using one port. I have two vlans on the port now (6 &9) and everything works fine, all switches communicate and end devices on the switches are also talking. There is a requirement to add a device towards the end of the chain which requires it to connect using Vlan1. Once I add Vlan1 to the port onthe 3750 I lose connectivity to all the HP switches.
View 4 Replies
View Related
Jan 16, 2013
This is regarding VLAN creation on C3750E switch.I want to create new Vlan 94 on this switch and also I want to allowed same interfaces like Vlan 95 & Vlan 96. [code]
View 7 Replies
View Related
Jan 8, 2013
I am trying to implement in the lab. I have 2 switches 3550 and 3750. my questions are:
1. why i can't see vlans in the running config on switch 3750 even after i created 3 vlans?
2. the 3750 is power over ethernet switch and i am trying to connect 3550 and 3750 thru cross over cable trunk link and the ports doesn't show up no light nothing. is it the right way of cabling.
View 6 Replies
View Related
May 21, 2012
We have a stack of switches that is at the max number of members allowed in the stack. Problem is we are running out of port density and need to add more ports. So instead of adding a whole new stack I would rather replace 2 of the 24-port swicthes with 48-port switches.
If the two 24-port swicthes we are removing are stack members and neither of them are the stack master, I should be able to replace the 24-port switches with the 48-port switches without bringing the master offline? If the new 48-port switches are running the same IOS version as the current 24-port swicthes, they should add themselves to the stack?Would I have to tell the new 48-port swicthes what switch numbers they are replacing in order for them to be added to the stack since we are at the max number of members?Also since the 48-port swicthes are replacing 24-port switches will the master give the 48-port switches the configuration for only the 24-ports?
View 11 Replies
View Related
Apr 22, 2012
I have 2 Cisco 6509 switches linked together via single Fibre as a trunk.I want to change this to a port channel where I will add another 3 fibre ports to the port channel but what order do I do this to minimise any disruption.
1-Configure PortChannel and add the 3 new ports, this will bring up the Port Channel but what effect will this have on traffic currently going over the single Trunk link? Will spanning tree go mad, how will switches react?
2-Convert existing Trunk link to Portchannel then add in new ports to PortChannel, I guess in doing this there will be a small hit on traffic as it changes to a port channel.
View 2 Replies
View Related
Dec 6, 2012
can i have 4 links from an ESX server to 6500 , each link represents a trunk link carries each the same 2 VLAN , 100 and 101 , keep port-channel out of the picture , does it work well?
View 12 Replies
View Related
Sep 21, 2012
We have 7 3560's in 7 different locations connected to our providor for wan access. Our provider has given us a copper cable at each point and we have connected it directly to our 3560 switch at each location. Each port is configured the same way at each location. Each switch is running eigrp.All of the switch ports on each switch are configured as a trunk and vlan 299 had the ip address for the eigrp connection: [code] This setup is working as each switch see's all of the other switches as an eigrp neighbor. We have also made sure that the switch at our head office has spanning tree priority for vlan 299.
So the problem is, if there is a change in the topology at one of the locations it usually causes one or more of the other connections to go down for some reason. We just cannot pinpoint what is causing this change. There are no log's or anything other than an eigrp hold time expired message.?
View 9 Replies
View Related
Jul 10, 2012
I have a pair of 3560's configured with dot1q trunks between them carrying a number of VLANs.
Once deployed there will be a requirement for these physical trunks to be disconnected from time to time. Knowing that this is inevitable I am trying to minimise the period of time for the trunks to recover once the physical connectivity is reinstated.
All of the VLANs on the switches are configured for Spanning Tree Rapid PVST. Current time for the trunks/VLANs to come up is around the 4 second mark.
View 11 Replies
View Related
Sep 2, 2012
Is it possible to use Port Security mechanism between two switch (3750 or 3560) ports while trunk has been configured? If it's not possible, is there any other way to ensure that no other Switch can be connected other then the one switch which has been configured/placed by a network engineer?
View 4 Replies
View Related
Mar 15, 2012
we have a scenario that consists of a Cisco 4507 series core switch with more than 20 vlans which is connected to a C2960G switch( in a nearby building) using a trunk by a fiber connection. Up to this point everyhting is fine . VTP domain is configured on the core switch and we have all of the 20 vlans present correctly on the edge 2960G wich is part of course of this same VTP domain.the fiber connection goes from core switch to a "in the middle location" where we have a fiber patch panel that is connected in a jumper style to another fiber patch panel going to the destination building where the C2960G sits.
Now imagine that Fiber connection from this middle location to the destination C2960 edge switch is down for any possible reason meanwhile the fiber connection from Core switch 4507 to the middle location is still intact.In the same time, in this middle location , we do have a wireless connection which links 1 Cisco 3750G switche ( a different infrastructure and different VTP domain) to another C3560G switch which sits on the same Room in the nearby destination building where we have the edge C2960G, An idea came to me is to connect one of the fiber port (core) in the intact fiber patch panel coming from Core switch 4507 TO an access vlan configured switchport in the 3750G switch ( this switchport will belong to a vlan designed only to trasmit the vlans on the trunk coming from 4507 core switch say VLAN 10) then connect one VLAN 10 access switchport to the destination C2960 edge switch ( the switchport on the c2960G is still a trunk)Will this solution work and all of the 20- 4507 core switch vlans arrive to the destination C2960G ? Or we do need something that tags the 2 VLAN 10 switchports like switchport dot1q tunnel like QinQ
View 2 Replies
View Related
Jun 6, 2012
I have several closets with Cisco 3560 on the edge that I'd like to change the vlan that's used for the management vlan on each. In the core I have a Cisco 6509 with Sup720's.
I'd like to do this by changing the native vlan on the trunk port on the core 6509 interface that connects to the 3560. and leave the management vlan on the 3560 as vlan 1.
Seems trivial but what I tried didn't work and I didn't have the window to troubleshoot. I'll paste the simplified configs for the interfaces below
!
6509 configs:
!
interface Vlan50ip address 172.16.50.2 255.255.255.0!interface FastEthernet
[Code]....
View 5 Replies
View Related
Feb 6, 2013
So I took a laptop with wireshark and plugged it into a nexus 5000 port that is configured as a trunk with 3 vlans allowed on it. The laptop was seeing all kinds of traffic on the wire, most of it was not involving my laptop.
For example: Server A VLAN 10= 10.10.10.1 Server B VLAN 20= 10.20.20.1 and wireshark laptop is plugged into a trunk port which is allowing those vlan's. The vlan's are routable.
10.10.10.3 is seeing the entire conversation when 10.10.10.1 backs up 10.20.20.1 even though it has no reason to see it. It is as if the trunk is spanning traffic to the laptop port. No span is setup however. It's really weird. This is not just broadcast traffic, but actual tcp taffic between Server A and B. Why would a trunk port see traffic between 2 other servers talking to each other on the vlan.
Trunk port configuration below:
Interface Ethernet 141/1/3
switchport mode trunk
switchport trunk allowed vlan 10, 20
View 5 Replies
View Related
Jan 20, 2012
I need adding a vlan to the trunks bundled in port channel. I know how to add v lans to a port channel with Cisco IOS but with CAT OS.
I have 2 ports bundled to form ether channel in switch which is running CAT OS. There are already few v lans allowed in the trunk of each interface. now I need to add one more v lan.
For Example:-
v lan 135 needs to be added in addition to the existing v lans.
clear trunk1/2 1-112,115,117-134,136-4094
set trunk 1/2 on dot1q 113-114,116,135
and similarly on the 2nd interface
so if I add vlan135 to the trunk one after another will it cause any service disruption?
View 3 Replies
View Related
Aug 15, 2012
I need to find out what is killing my Ethernet wan circuit urgently, It is a Ethernet trunk port with v lans tagged across it.
its a 3560x switch.
I configured span with the replicate keyword, but I'm not seeing all the traffic I'm sure.
I'm using wire shark.
Is there anything I can do to find what is causing this?
View 2 Replies
View Related
Feb 15, 2012
I'm trying to trace a host and I'm getting stuck at the port channel mac addresses. I need to find out where the server is connected to and the switch it lives on.
Please read below:
Step 1) Log into the core (MSFC): Code...
How do I find out where this physical server lives? I keep getting the mac for the trunk ports which is being used for all VLANs.
The server is hanging off some switch but I need to track it down to the last end.
View 1 Replies
View Related
Aug 27, 2012
I have a Cisco Wireless LAN Controller WCL2112 model. It's currently plugged into an HP Procurve switch on a trunk port. That HP switch is plugged into my Cisco stack on a trunk port. I can reach the WCL just fine through the LAN. But when I plug the WCL directly into the Cisco stack on a trunk port, I can't reach the WCL at all, unless I connect to it over wireless. The interface shows it's conneccted and up/up. But no communications are sent across the line. I did a wireshark and can see only ARP request from the WCL. The trunk port on the stack is set to:
interface GigabitEthernet1/0/1
switchport trunk encapsulation dot1q
switchport mode trunk
The WCL has 3 VLAN's on it and the SSID of VLAN 1 is our office wireless. If that matters. .The Cisco Stack is 4 switches. cisco WS-C3750X-48P
View 3 Replies
View Related
Oct 11, 2010
Any way to test in a lab what would happen if a tech mistakingly added "switchport voice vlan XX" to a trunk port? I am try to do some RCA on an issue and this has been identified as a possible cause by one of my techs.
The config is Switch1------Switch2--------Switch3 Each interswitch connection is configured as a dot1q trunk with all vlans allowed. The link between switch2 and 3 is where switchport voice vlan 10 was added. Switch1 is a 3750 and 2/3 are 3560's.
View 8 Replies
View Related
Feb 12, 2012
we recently aquired a managed services job and have to do a overhaul of the vlan configs and have a whole dozen WC2948G's trunk between a set of ports as well as trunk out a LAG channel setup to non cisco equipment. the deal is the lacp-channel works properly on both ends but no routing of vlans between ports and between the lag trunk are working.
theres alot of settings in the config and im planning on clearing it and starting from scratch but before i do i want to know where my problem lies.
[code]...
View 6 Replies
View Related
Nov 2, 2011
i have an issue to connect a trunk between cisco switch and extreme switch i have many vlans that i want to cross via a link between cisco 3750 switch and a Extreme Alpine 3800 switch
View 12 Replies
View Related
Apr 10, 2012
We are using the SG300 series switches, and have come across an issue where we need to block ARP broadcasts based on IP.
we have multiple computers, each with only one ethernet adapter, each adapter has two IPs configured, 10.10.10.x and 192.168.0.100.All machines have the same 192.168.0.100 address (Used for applications/hardware running locally to that machine and this IP cannot be changed).
When the machines are connected to the network, ARP is advertising BOTH the 10.10.10.x address and the 192.168.0.100 address.
As all machines have the same 192 address we receive IP conflict notifications on each machine.
How can the ARP broadcasts for the 192 address range be blocked?
View 1 Replies
View Related
May 17, 2013
ARP broadcasts not reaching all VLAN ports on 3550
Cisco 3550, interface Vlan9
ip address 1.1.1.1 255.255.255.240 secondary
ip address 3.3.3.3 255.255.255.240
[Code].....
View 5 Replies
View Related
Apr 11, 2013
Is there really any reason why you wouldn't use spanning-tree portfast on a trunk port other than a trunk between two switches? We have it enabled on all ports except for the fiber trunk between two non-stacked switches and the trunk ports connected to our Astaro firewall.I'd like to enable it on the ports to the firewall unless that would cause issues.
View 9 Replies
View Related
May 19, 2013
I have a stack of 4 3750 Switches.
1. WS-C3750G-12S
2. WS-C3750G-12S
3. WS-C3750X-48P
4. WS-C3750X-48P
The stack cable connected to Switch 1 Port 1 and Switch 4 Port 2 will not come back online. The logs show that there was a Stack line change. I have replaced the 1 meter Stack cable from Switch 1 to Switch 4 three times and it still does not come back online. This is the part that is interesting.. I have disconnected Port 1 Switch 4 and connected it to Port 2 Switch 4 and then Switch 4 came back online. This made me think Port 2 on Switch 4 was working correctly. Then I disconnected Port 2 Switch 1 and connected it to Port 1 Switch 1 and then Switch 1 came back online.
View 1 Replies
View Related
Mar 11, 2013
have a cable i think is bad, is it possiable to switch the cable out without causing any downtime to the switch or connected devices?
HQ-1st-Flr-Stack#show switch stack-ports summary
Switch#/ Stack Neighbor Cable Link Link Sync # In
Port# Port Length OK Active OK Changes Loopback
Status To LinkOK
[Code].....
View 15 Replies
View Related
Nov 7, 2011
I am trying to configure a 3750 48 port switch and having trouble with getting it to see the sfp. I just want to set up the router with a pretty basic set up since I am using it for a ping test between 2 buildings, via fiber. How I can enable the sfp port?
View 3 Replies
View Related
