Questions tagged [switch]

For questions about network switches, the term commonly refers to a multi-port network bridge that processes and routes data at the data link layer (layer 2) of the OSI model.

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Cisco nexus 9396 rebooted with reason xbar_client

Today my one of cisco nexus 9396PX switch got rebooted and this is what i found, based on following logs what could be wrong? We don't have Cisco support for this switch, trying to see if i can get ...
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Why is routing not working on my Dell N2048 switch

I am in the process of replacing some older Dell Powerconnect switches with a some Dell N2048 switches. While doing this I wanted to go ahead and segregate certain areas of my network using VLANs. ...
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Cisco nexus STP loopguard

I have cisco nexus switches in vPC and they are connected to HP c7000 blade center switches and all my c7000 blade server has Linux Bridge is running, i believe something went wrong somewhere in Linux ...
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Why does RSTP send proposal bit and agreement bit as '1' initially?

From a recent Wireshark capture of a RSTP BPDU on a switch, both proposal and agreement bits were set to '1'. In my understanding, initially both switches 'propose' themselves as root. The better root ...
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HP 5500 JD374A Port naming convention

Hi to all :) To most of you it'll prolly sound like a very silly question to ask, however to me as a fresh network trainee the answer is unfortunately not so obvious. So, the question is whether the ...
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If one of hub is damaged,will it cause others hub damage too?why can't i enable the rapid dual homing

There is a multi-ring topology, combined with 8 Hubs and 2 switches, i want to ask two questions 1. If H3 is damaged,but the fiber is still ok, will H2 damage too in the future? i have thinking to ...
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855 views

How do I split static IPs from an ISP for separate usage?

I have a lot of IT experience/consulting, but want to test what I have done against some of the real experts hre in the networking field so I can keep learning and do what's best. I have ISPs with 5 ...
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473 views

Cisco nexus spanning-tree logging to syslog

I am trying to send my spanning-tree events to remote syslog but somehow it doesn't work, This is what i have in my config. N3K# sh run | grep logg logging level spanning-tree 7 logging server 172.29....
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Cisco 2960 not receiving dhcp from the router

I have a problem with Dhcp of some the Vlans. here is how my network is : I have a router ASR1001, which connects 15 switches(2960) as a ring topology. each switch has a subinterface of the router ...
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Auto smart ports macros triggers

My question is simple: I have a Catalyst 3560-X series switch and the below macro applied when i connect my laptop to the switch and it's working fine . function My_laptop_func() { if [[ $LINKUP == ...
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Allow outgoing connections

I have an Arista switch (EOS) and I'm having trouble allowing outgoing connection from the switch to the outside. Using tcpdump I can see that no packets are being allowed. This has an impact on DNS ...
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Multiple switch groups on a Dell Powerconnect 5448 Switch

I am new to managed switches. I have a Dell 5448 48-port switch. I would like to configure it as six separate groups of unmanaged 8-port switches. Each group of 8-ports would share all traffic within ...
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Spanning tree loop prevention

Can I get some advice on what STP features to enable as best practice please, mainly to mitigate loops? In the past a user mistakenly connected two floor ports together causing a loop. Below are the ...
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1 answer
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I upgraded a Cisco switch to a newer model with different SNMP OIDs. Can I have the new switch receive the old OID and report values from the new OID?

I upgraded from a Cisco SG300-10MP to a Cisco SG350-10MP. A piece of software is looking for the value from 1.3.6.1.2.2.1.8.50, but the OID on the new switch is 1.3.6.1.2.2.1.8.2. The final number ...
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100 Mbps vs 1 Gbps in a network

I have a network with an older HP 1400-24G un-managed switch. A while back I noticed that backup for a SQL server database took 15 minutes. Using the performance monitor I found the Ethernet ...
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J9450A HP 1810-24G Switch firmware upgrade

I'm trying to upgrade the firmware on my J9450A HP 1810-24G Switch, which presently has firmware P.1.6, eCos-2.0 The firmware-update-for-an-1810 question is out there on the internet, but the ...
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What are non-learning and learning VLANs?

I was going through some IEEE standards for switches (IEEE 802.1aq and IEEE 802.1Qca), and came upon a terminology of learning and non-learning VLANs. I read that learning VLANs are used in Shortest ...
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HP ProCurve Switch 4100 series - Checking PSU status & S/N from the CLI

Do you know if there is any CLI command available on the very old HPE Procurve 4108gl/J4865A switches where you can see how many PSUs are installed in the chassis, what's their current status and ...
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How to block telnet access for one particular network from all networks except one using Extended ACL

Scenerio is given in the picture. I want to block all the networks except 192.168.5.128/25 from doing telnet of 192.168.5.0/25.
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Untagged VLAN in EVPN+VxLAN

I am dealing with very strange issue but wanted to check with experts if i am doing anything stupid or not. I have small size EVPN+VxLAN clos network (OSFP+iBGP+Multicast+Arp-suppression (no ...
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Using a switch to dynamically connect and disconnect multiple devices together in a point to point configuration

I have an interesting issue. I have to use a switch to dynamically connect and disconnect multiple devices together in a point to point configuration, without changing anything on the end user side. ...
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Connecting layer 3 switches together without trunking

I currently have 2x Juniper EX4200 and I'm looking into changing it into Ubiquiti EdgeSwitchs. The diagram: SW01 and SW02 are connected to each other using OSPF P2P. Both of the switches have their ...
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Why my ae interface Link type is down but the physical interface is up?

Why my ae interface Link type is down but the physical interface is up? In my convergence layer Switch, I use two Juniper EX4300 devices realize the Stack: so there have xe-0/0/x and xe-1/0/x ...
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How to keep the VRRP failover mechanism?

referring to the diagram below, we have 2 VLAN's for voice, primary route for VLAN1 (red) is the left side, and VLAN2 (green) is the right. As it stands we have a nice easy setup, where VRRP kicks ...
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825 views

Even ips pinging but odd ips not pinging

We have following network, and i have multiple host connected to TOR switches configured with public IPs. We have HSRP running on vPC switches. interface Vlan100 description *** Public VLAN *** ...
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HP ProCurve 6120XG with Cisco configuration

ProCurve 6120XG Blade Switch with Cisco trunk I have c7000 HP blade Center with ProCurve 6120XG Blade Switch and i am creating trunk to my TOR1 Cisco switch (Nexus 3064), but having issue related VLAN ...
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1 vote
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How does a Switch Fabric Module work internally?

I am interested how does a switch fabric module work internally. What interfaces does it use to physically connect the I/O modules on switches? Where are the CAM / MAC tables of the switch? Are ...
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How does Fabric Connect protocol work?

What are the algorithms that are used by Fabric Connect protocol/protocols to choose the best path to forward a packet? I know that Fabric Connect is used to replace the Spanning Tree Protocol that ...
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3com 5500G migration to force10 s4810

I am doing this migration with these 3com switches.So our client told me that the configuration was made for a network administrator who was fired some years ago. So I dont have any kind of ...
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2 answers
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Switch 3550 password default password

What is the Cisco 3550 default password? I lose the password due some power outage while I was programming. I did reboot, and try the recovery password but doesnt work.
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Optimizing access control lists on a Cisco SG500X-48 Small Business switch

I am trying to optimize the access control list rules on a Cisco SG500X-48 Small Business switch (on Layer 3). The general aim is to regulate the traffic between two VLANs (e.g., 10 and 30) in such a ...
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Wireless guest vlan issue

I am trying to separate the traffic of a wireless controller using VLANs. I have a Cisco 4400 wireless LAN controller configured to connect to the guest VLAN on an HP ProCurve 5412zl switch. The ...
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1 vote
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233 views

VLAN issue in HP 5406 switch after a power outage

Last week we had a power outage. When power came back, our HP switches came back online but with a problem. A few VLANs in our HP 5406 switches did not get an IP address from DHCP server, the other ...
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Dell Switch N3048 with PowerConnect 6248

I have two Dell switches and its a classical VLAN Scenario that does not want to work. PowerConnect 6248 is connected to the outside world and from there i like to bring new subnet ( this is already ...
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1 vote
0 answers
685 views

PowerConnect 2808 and syslog

I have a pair of Dell PowerConnect 2808 managed switches. I am attempting to enable syslog on them, but not having any luck. I have searched the web interface, used telnet to log into the CLI ...
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1 vote
0 answers
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Dual Internet connections in active/standby mode without BGP

hello everyone attached is my diagram in which i am facing problem as you can see i have two internet links from two ISPs in which i want failover between two ISPs without using BGP or NAT because i ...
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1 vote
2 answers
146 views

Colocation Rack Networking

I'm a sysadmin tasked with finding a managed service provider or networking contractor to build out our new colo space networking. I'm hoping to get some input to make sure I don't sound like an idiot ...
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1 vote
1 answer
839 views

Cisco ASA context OSPF configuration issue

I've two cisco ASA configured in active/active HA. ASA is connected to switch with port-channel. Switch configuration: interface Port-channel47 description ASA2 switchport mode trunk switchport ...
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Local network with two switches and a router

So im a newbie in networking and i have a assignment. I gotta install the following network: PC100.100/25 (win/linux)->switch(non manageable) -> Router 100.1or90.1/25(on ubuntu) -> Switch(non ...
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Admin IOU L3 switch

Problem with IOU l2 switch By Konstantinos Dimos July 31, 2022 at 3:12 UTC Hi, under Ubuntu 22.04 LTS, gns3 and local server I am trying to manage switch IOU L3 switch, although at the begining I was ...
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1 answer
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Noob: i design a network for 156 computers/4 printers, need help in few things

Sorry if this stupid questions: I just learn networking like a week. Lets say company xyz have 39 computers and 1 printer in each floor, there are 4 floors, total amount of computers is 156computers ...
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42 views

Capture switched traffic on fortigate

I have a fortigate 40F with an lan1 to lan4 configured as an hardware switch (lan). I would like to capture switched traffic between hosts, even if it's not in the same IP subnet than the lan ...
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How FDB (Filtering Database) is filled out

I would like to understand what is used as a VLAN column in the FDB. For ACCESS port it is PVID if frame untagged or frame VID if frame is tagged, for TRUNK it is allowed VLANs? We can represent the ...
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Managed Switch, Setting up VLAN Tagged, Untagged, allowed & tagged only etc

Looking for some help setting up a Dell PowerConnect 2724. 1st time setting one of these up. The best graphic I could find to explain my setup: My router DHCP is enabled so it will provide IP ...
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Changing boot variables

I'm new to networking/cisco gear and need some guidance. I'm gearing up to upgrade the code on a 3650 from 03.06.04E to 16.12.05b. I've done this once successfully but ran into a switch with a ...
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1 answer
87 views

Can anyone explain the introduction of Rapid Dual Homing to me?what is the main function of rapid dual homing?

I read some information about Rapid Dual Homing from JetNet 5020G,the figure below is the introduction of Rapid Dual Homing. Honestly,i don't understand why can the rapid dual homing have multiple ...
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37 views

Update IOS on Cisco CGS2520 Switch

I need to update the IOS on a Cisco CGS2520 Switch. Not stacked, single switch I have never done this before and I have a couple questions. I do not have physical access to the switch. Looking at the ...
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48 views

How do I load VLAN database between switches (CISCO 2960)?

I glad for any help on this topic -- netanel
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63 views

h3c switch - get which trunk group that a port belongs to via SNMP

Switch: HP FF 12900 with JG857A, JG626A and JG623A modules I want to get which trunk group a port is belongs to via SNMP on my h3c core switch. Which MIB and OID can I use to get that data via SNMP? A ...
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221 views

Can ping from VPC 1 to router and VPC2, but can't ping from switch to VPC2 or router

I have a simple, linear topology in GNS3 that goes like this. VPC1 > Switch > Router > VPC2 I have the default static IP Routes on the router set to 0.0.0.0 0.0.0.0 Ethernet0/1 and Ethernet1/...
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