Questions tagged [vlan]

For questions about Virtual LANs (VLANs) which are used to divide what otherwise would be a single OSI layer-2 broadcast domain into multiple, logical OSI layer-2 broadcast domains.

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Arp Protect in dynamic VLAN environment

I am using 802.1x authentication with dynamic Vlan assignment(CPPM). As you may know, when a user logges in to their computer, SW attaches the user port to related Vlan. Thinking the scenario in which ...
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1answer
55 views

Using L2 switches for multiple connection

For proof-of-concept, I need to build a small network but have not enough L2 switches.Is there anybody help to solve this problem? Below is the network I want to build. L3SW---L2SW1---L2SW2---RT---...
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47 views

Cannot create connection between two routers in same VLAN via switch

I currently have a Cisco 2960-24TT switch (switch1) and a Cisco 1841 router (router1) that form part of my core network connecting other VLANs and devices. The two ports on router1 have been ...
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28 views

LAG and VLAN Problems

I have an extended star network between two buildings. In each building I have a "Main" switch. The two Dell N1524 switches are connected via 4 fibre optic links over SFP+. Now the 4 links are ...
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1answer
53 views

Why is this subnet config required by my vlan “snake topology”?

I must validate the bandwidth on all 8 ports of a switch. We intend to do this with a "snake" topology as described in this article: http://thenetworksherpa.com/test-throughput-alchemy-using-a-snake-...
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2answers
134 views

Configuring a network for 100% isolation (for security)

I'm configuring a LAN for an office. It's a new setup, and therefore there are desktops but no servers and no PC-to-PC communications - everything is on the cloud. The exception to this are several ...
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1answer
31 views

Using a VLAN to Completely Isolate Devices from the Internet & Other VLANs

I have a Cisco SG350-10P Managed Switch, and currently have two VLANS on it, the default VLAN 1 and VLAN 10. I want devices connected to VLAN 10 to have no ability to communicate with the internet or ...
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1answer
41 views

Correct vlan/interface config for connection to upstream provider network

We have recently switched from HP Procurve series to HP Comware based switches. A configuration which has been working on Procurve doesn't seem to work on Comware. Here are the details: The provider ...
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1answer
29 views

Is performance worse routing between two vlans on one interface than routing between two NICs with no vlans?

I have a Linux router with one interface that is connected to a switch in port 2. Port 2 on the switch is a member of vlan2(ISP) and vlan3 (office devices). My router is currently routing between ...
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0answers
38 views

PVLANs/Port isolation in IPv6 networks

We're currently using port isolation to prevent communication between computers on the same vlan and use client isolation on our guest wifi. The reason for having this enabled is to prevent unwanted ...
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2answers
56 views

Typical LANs with VLANs

When using switches which support VLANs with switches which doesn't support VLANs, can they be mixed with each other in the same network?
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2answers
79 views

VLANs vs subnets pros and cons

What are the pros and cons of designing an entire network using VLANs rather than design the network only using subnets?
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1answer
43 views

CSMA/CD in VLANs query

Ethernet is based on CSMA/CD. When using VLANs, the number of stations can become very high, making CSMA/CD inefficient. Are there any mechanisms that VLANs use to overcome this?
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5answers
4k views

VLANs over internet

How does VLANs work over the internet and span across multiple geographical locations? VLAN headers are removed when frames move to another switch or a router? How does it happen?
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2answers
54 views

Cisco Switch without VLAN support?

I've been reading about VLAN and wondering is there any Cisco Switches that do not support VLAN? So far, all switches that I found do support VLAN. This is one of the example in my lab. Cisco-Switch-...
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1answer
67 views

ICMP message doesn't leave NIC of PC

I got an interVLAN configuration a.k.a 'Router on a Stick'. I can ping all the workstations with each other, except PC9 (refer to image). I did a simulation and found that the packet does not even ...
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4answers
102 views

Are VLANs the same on different brands of devices?

I have 3 switches from different brand and I want to configure VLAN on them Do these switches have to be from the same brand (Cisco or others)to be able to configure VLANs?
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1answer
57 views

How can I get OSPF to see the VLANS that are trunked through the gigabit port

I am relatively new to this and I have been trying various configs but nothing is catching. I have three routers, with various vlans. The vlans are working. The routers are seeing each other using ...
3
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1answer
62 views

Router can ping and resolve hostnames, but VLANs and switch cannot

I recently installed an Adtran Netvanta 4430 to perform some basic VLANs on a network with a little bit of inter-VLAN routing, and I'm having a few odd issues, probably attributed to my inexperience ...
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1answer
72 views

What is the purpose of native VLAN on a trunk link?

Most VLAN articles I've read recommend avoid using VLAN1 for ports with untagged traffic (aka access ports). I've heard enough of this nonsense. Except for the reserved values of 0x000 and 0xFFF, a ...
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2answers
67 views

Is there a way to manage IP space with only a switch?

Is this scheme possible? External provider = External provider of the internet Generally speaking, is there a way to assign a public IP address individually for each server to be used when SFP+ port ...
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1answer
44 views

Access a device connected in another switch

I have theses two switches, 3Com 4500 and 3Com 2928. 3Com 4500 - IP: 20.20.X.X ; Mask: 255.255.240.0 3Com 2928 - IP: 192.168.1.X; Mask: 255.255.255.0 There is a printer(20.20.2.1) connected in the ...
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6answers
3k views

packet routing between subnets on same vlan

I am trying to understand how packets are routed within the same VLAN. I understand that typically there should be a 1:1 mapping between VLANs and Subnets. However if i deploy the following ...
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3answers
44 views

Ip phone problem cannot get an ip address from dhcp using other vlans except from vlan 1

i am trying to understand native vlans. when i use vlan 1 it worked and it provides an ip address to my ip phone. When using vlan 100 it does not work even i tried using native trunking on it. please ...
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1answer
35 views

Device on VLAN is accessible from VPN but not from LAN

I have a Meraki MX84 with two VLANs, 192.168.213.0/24 (main subnet), and 10.4.213.0/24. I have an EdgeRouter 12P connected to the MX with static WAN IP 10.4.213.2. The issue is: when I VPN into the MX ...
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0answers
100 views

How to check vlan interface traffic on Cisco nexus 9k

I have Cisco N9K-C9396PX L3 switch which has VLAN interface configured for my LAN gateway and i want to monitor how much traffic vlanXXX handling, I have configured SNMP monitoring to pull interface ...
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1answer
42 views

Does Network segmentation work using different switches connecting to router?

I just learnt basic networking. If I have 2 departments which I do not want them to access each other's networks, does using two layer 2 switches connecting to the router does the job or do I need a ...
2
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3answers
340 views

Cisco ASA 5512X does not allow connections across VLANs to internet

First time doing a network, I'm a software guy normally. I am setting up a network to share and internet connections to multiple properties. The goal is to segment each property onto its own VLAN. I ...
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1answer
72 views

EIGRP Holding Time Expire on VLAN Interfaces

I configure 2 Layer 3 Switches with VLANs and EIGRP route. But it always return a message like this : %DUAL-5-NBRCHANGE: IP-EIGRP 2019: Neighbor 192.168.20.253 (Vlan20) is down: holding time expired ...
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2answers
89 views

Cisco Catalyst 9410 - Using Default Gateway versus ARPing for locally connected host

I may be missing something extremely simple here, but im at loss trying to figure out what this Nexus switch is doing. Here is the topology: DISCLAIMER! I had made a mistake on the diagram by ...
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1answer
57 views

Cisco 3750: SNMP

On my Cisco 3750G, i have SNMPV3 enabled, this is working perfectly with Zabbix. I would like to separate production flows from supervision flows, Do you know if it's possible to enable SNMP ...
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1answer
33 views

STP Priority field and 4 bits in multiples of 4096

For the STP Priority Field, how do you get "multiples of 4096" out of 4 bits?
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1answer
38 views

Routing between 2 VLANs with one HP Switch

I need help with VLAN: I have a WiFi AP with the IP 192.168.100.190. There are 2 SSIDs with VLAN 1 and 2 created. As a router I have a Sophos UTM with the IP 192.168.100.199. Furthermore, I have an ...
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3answers
126 views

Difference between Port (all VLANs allowed) and Trunk

I have a very basic background on networking Cisco (2960 switch), and realize that Fortiswitch 224E has the option to allow many VLANs in a port: On the other hand, is the trunk (which I assume is ...
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1answer
40 views

Connect 2 VLANs on Cisco SG300 with cable

I have a Cisco SG300 with 2 VLANs enabled, half the switch ports are on one VLAN, half is on the other. Both VLANs use the same subnet. I want traffic to travel between the 2 VLANs. I thought the 2 ...
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1answer
56 views

Can different VLANs have same subnet? [duplicate]

When talking about VLANs I often see examples like this: VLAN 10 - 10.0.10.0/24 VLAN 20 - 10.0.20.0/24 Different subnets yet different VLANs. I understand this is a must if we want communication ...
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1answer
53 views

Vlan Command Issues on Cisco Switches

I'm new to cisco equipment. I have GNS3 emulating an L3 switch whose image is "i86bi-linux-l3-adventerprisek9-15.5.2T.bin". I want to create a cable network with 802.1x and vlan authentication. For ...
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3answers
30 views

Can we set filewall rule to control with in subnet? and also if we use 2 subnet on same interface Is this effect to firewall rule?

Can we set filewall rule to control with in subnet? as in picture Can we use firewall to controll PC0 to access only some port on PC1 ? if we set gateway to router , Is it will alway go to router ...
0
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1answer
27 views

BNT Layer2/3 Switch & Cisco SG200 VLAN

I'm trying to set up a VLAN for my staging environment, but I'm having trouble. Here's my network layout: +--------------------+ | [1] [2] [3] [4] | Ubiquiti USG-PRO-4 +--|----|----|-------+ |...
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1answer
90 views

Remove VLAN tag from incoming traffic (Ubiquiti Edgerouter)

On eth4 I have incoming traffic from the WiFi AP. Some is tagged with VID 102 and some with VID 950. I want the Ubiquiti Edgerouter (which is currently acting as a managed switch) to take the 950 VLAN ...
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1answer
118 views

VLAN routing over multiple routers(RIPv2)

I am currently working on a scenario to get a better understanding of the RIPv2 routing protocol but am currently stuck. Please see my picture below to get a better understanding of what I am trying ...
2
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0answers
124 views

Cisco switch SVI MAC address strange problem [closed]

I am having the SVI MAC address problem on my switch (3850) The MAC address of the SVI (VLAN2) is currently conflicting with another switch. Why did this switch decide to use 7018.xxx.xxx MAC ...
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1answer
43 views

Setting all switchports as tagged for 200 x VLANs?

question: should I expect any performance hit from enabling 210x tagged VLANs on ALL 24x ports of a switch (or alternatively setting ALL 24x ports as trunk ports) background / equipment: We have a ...
0
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1answer
59 views

How do VLANs Work? Some Basic Questions: [closed]

I've recently started looking into VLANs. I am a network novice so bear with me please:). I have a few questions regarding VLANs. I understand that certain managed switches allow you to create VLANs. ...
2
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3answers
143 views

What's the advantage of having VLANs if you enable inter-vlan routing?

If you configure VLANs with each having their own subnets, is there a point to have them if inter-vlan routing is enabled? Since VLANs will have access to other VLANs, the security argument is not ...
2
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1answer
72 views

Upgrading Cisco 819 to 809, can I connect devices to 2 routed ports and be on same subnet?

The company I work for has multiple remote "IoT" style sites connected back to the datacenter via a Cisco 819 cellular router. We are in the process of upgrading these to the newer Cisco IR809 routers ...
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1answer
60 views

802.1ad (QinQ) and router

I am a little bit confused. Is router aware of VLAN tag? What happen when tagged frame comes to router? (without any extra setting like encapsulation) Or what happen when QinQ frame comes to router? ...
2
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1answer
93 views

Restructuring office network advice and How to go about VLAN setup?

Wanted to get some advice and assurance that I’m on the right track for re-configuring our office network. Current setup: FortiGate100D with 2 physical network interfaces, network-1 used for regular ...
3
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1answer
160 views

Access control on Cisco router with switchports?

I am working with a series 800 router which has inbuilt switchports. I want to use 2 switchports for a VLAN (say VLAN 100). On one port will have devices: 192.168.1.10 192.168.1.30 Connected to ...
4
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3answers
399 views

Leaf-Spine network without routing

If I have a leaf-spine network with all the servers on the same subnet, say 10.10.0.0/16, do I need a router (or l3) since everything is on the same network and the network is flat?

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