Questions tagged [trunk]

For questions about trunks, layer-2 links across which traffic for multiple VLANs travel.

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2answers
219 views

Can't add VLAN in the “allowed VLAN”

Why is this command not accepted? switchport trunk allowed vlan add 52,160,176,177,247 I tried adding only one VLAN; it's also not accepted. No error is shown or anything; it's just not showing when ...
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2answers
46 views

How to connect two different subnets

This may be a very basic question, but I'm a networking newbie. So I have the following setup: Server with one NIC on IP 192.168.10.1/24 (Network A). It is not possible to change this IP. Computer A ...
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1answer
27 views

VLAN not working in Comtrend switch

I'm trying to configure VLANs with 3 switches Comtrend (2- CNGE2FE8MSPOE + 1- CWGE26FX2TX24MSPOE) and it's not working as I expect. It's the first time that I work with VLAN and I don't know If I ...
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2answers
72 views

How to monitor vlan using SMNP?

I am a newbie to building a monitor system using Prometheus and SNMP exporter, I have succeeded get metric from the physical interface, but I want to monitor VLAN on a trunk port, is that possible ? ...
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2answers
58 views

I cannot Encapsulate on Router

I have VLAN10 and VLAN20, I am trying to communicate between computers with the same VLAN on the following setup: I want to apply encapsulation from Router but it doesn't seem to recognize ...
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1answer
969 views

difference between switchport trunk encapsulation dot1q and switchport mode trunk

I am new to network engineering and I am currently delving deep into L2 functionality.what is the difference between these two commands: 1 switchport trunk encapsulation dot1q 2 switchport mode trunk ...
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1answer
72 views

Trunking multiple VLANs into a single trunk port on a 3650 Switch

Morning: I'm new to the world of Cisco Packet tracer, and I am creating a network for a uni project. So far, what I have is: 5 VLANs (subnetted to 192.168.2.0/26, 192.168.3.0/36 etc) All are ...
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1answer
98 views

Why some situations, PC can connected to trunk port and work fine?

I want to know about tagged and untagged vlan mechanism then I try to configure like this When I connected PC3 to trunk port on Packet Tracer, It doesn't work and a switch dropped PC3's frame if I ...
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2answers
39 views

If we already have default VLAN, Why we need Native VLAN? [duplicate]

What is the need of Native VLAN and default VLAN. How they are related? Can Somebody explain this in detail?
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2answers
73 views

ping in the same VLAN with multiple switches in between

Refreshing VLAN knowledge with PT7.3, I came across some unexpected behavior. Why does a chain of switches having proper trunk configuration between them DROP packets? Trying to ping hosts from the ...
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2answers
40 views

IOS. Whats the difference between these 2 commands

I am completing an online course for the network+ and am going through one of the labs. Here is a diagram of the network in question. Specifically I have a switch with 24 fast ethernet ports and ...
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1answer
161 views

Why can't I connect to PfSense via the switch?

Our current firwall is deprecated and we decided to exchange it with an PfSense server. In my test setup I configured the interfaces as follows: igb0 = WAN enabled igb1 = LAN (should be VLAN trunk ...
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2answers
48 views

VTP pruning used in combination with allowed vlan

I have a network on which most of the switches are running VTP client/server mode. Few switches are not yet in that mode - for specific customization or because they simply cannot handle it. Thinking ...
3
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1answer
89 views

cisco switchport trunk native vlan

we have switch catalyst 3850 and we need to enable the PXE boot on a port configured in trunk with configured three VLAN (4040, 4050 and 4060). To permit the PXE boot and deploy to work we set on the ...
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2answers
111 views

Cisco router on a stick with public ip wan (ISP)gateway

I am trying to create a router on a stick with an outside facing sub-interface with a public IP from an ISP. I have tried to configure NAT and routing but I just cant get to ping the internet. I'm ...
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1answer
43 views

How to define trunk port between vmware esxi host 6.5 and switch? [closed]

I create some virtual machine in different vlan but i can not set trunk port from vmware to transfer vlan information.
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1answer
121 views

Removing VLANs from core trunks (.1q)…?

I am a little embarrassed I do not know the answer to this already, well I think I know the answer but I am not 100% sure and this I need to be 100% sure on. We have several core .1q trunks that we ...
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2answers
564 views

Can a single subnet work across several switches?

New to networking and studying hard but limited access to a kit to try things at the moment... My question is - if I had, for example, two Layer-2 switches cable connected, could I have devices on ...
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1answer
43 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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1answer
63 views

Why Access ports should have the same trunk native vlan? [closed]

In the current switch Management VLAN is 48. Can you please someone explain it to me, why we dont give trunk native VLAN as 48, and we configure the same as access VLAN? Thanks in advance.
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1answer
1k views

Why STP has to be disable on Trunk Ports?

I have 5 Switches on a Private Network 10.0.0.0/8 with 8 Vlans. On Access ports is running Rapid STP. On Trunk Ports between Switches should i disable STP or not? I would be very pleased if someone ...
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4answers
82 views

Confused in using the ports for trunking mode

The ports are as follows: for the switch on the left side the upper port is fa0/1, below it is fa 1/1 and below fa1/1 is fa2/1. For the switch in the middle the left port is fa0/1 and the right port ...
4
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1answer
502 views

Best Practice for Voice and Data VLAN on single port

We have multiple interfaces currently configured with the below on our Cisco 3750x switch. interface GigabitEthernet1/0/21 switchport access vlan 4 switchport trunk encapsulation dot1q switchport ...
3
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1answer
2k views

spanning-tree port type edge trunk on port-channel vs physical interface

If i configure spanning-tree port type edge trunk on physical interface instead of port-channel does that work? Or i have to do spanning-tree port type edge trunk on port-channel ? Example: ...
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2answers
1k views

Portfast on Trunk port

Why shouldn't I activate portfast on a trunking port for a Cisco switch? I do understand that it could cause a loop on the the network, but I still cant wrap my head around the concept.
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3answers
861 views

Do VLANs within a subnet need to have their own subnet for router on a stick?

I have been creating a network lab in packet tracer for practice. I have 3 vlans in subnet A and I am trying to configure router on a stick at gig6/0 on the bottom left of the image. Do I need to ...
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1answer
388 views

Assigning a single switchport to different VLANs

I've been trying to figure out how to achieve the outcome below. VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- ...
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1answer
60 views

when to make a port dynamic desirable instead of trunk?

i'm reading CCNA stuff and just got stuck in this issue: i read some articles about DTP and trunking but didn't understand when to make a port trunk and when make it dynamic desirable ? in what case ...
0
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1answer
637 views

Quanta LB6M : how to make trunk port

My hardware is (quanta10g-uha) #show hardware Switch: 1 System Description............................. Quanta LB6M, 1.2.0.14, Linux 2.6.21.7 ...
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1answer
103 views

Dhcp Broadcast Through Switches

Think of a pc connected to switch1. Sw1 is connected to sw2(trunk port on both switches) and sw2 is connected to a router(dhcp server). Pc sends a dhcp broadcast. Does sw1 passes the broadcast through ...
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2answers
796 views

Create a dead end vLAN for untagged/native between Aruba and Cisco switches

I would like to use a dead vLAN as the native/untagged vLAN on trunk feeds as a security best practice. The trunk feed is between a Cisco and Aruba switch. On Cisco switch, the vLAN is left out of the ...
4
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1answer
191 views

What are reasons to configure a Voice VLAN using the Auxillary VLAN feature instead of a Trunk + Native vLAN

Imagine this topology: [PC] ------- [VOIP Phone] ------- [eth0/0 on a Switch] And this configuration on the switch: vlan 22 name DATA vlan 33 name VOICE There are two ways to have both the PC'...
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1answer
189 views

What is VLAN Hopping

I am starting on my journey into the world of Networking and have come across a term called VLAN hopping. The sentence I read was that if the Native VLAN on two switches connected to each other via ...
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2answers
107 views

Partitioning between VLAN in a Trunk switch architecture

Supposing we have a Trunk switch architecture with multiple VLANs as shown below : A computer that belongs to the VLAN1 on the first switch (from the left) will be able to communicate with the VLAN1 ...
3
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1answer
397 views

Need help/advice on basic network setup involving security cameras, guest access, and VLANs

At some point, I'd like to move from a single, flat, network to having a more secure network using VLANs. I have an idea of what I would want, I just don't fully understand some details of Native ...
2
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2answers
81 views

Use of VLAN allowed feature and security risk associated with not configuring it

if i have 3 vlans say, 10,20 ,30 if i don't assign vlan allowed to trunk port , what are the security risks i could face if i am using default vlan allowed range what are the benefits of VLAN ...
3
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2answers
2k views

Does 802.1Q protocol will remove the VLAN tag in the received place?

Does 802.1Q protocol will remove the VLAN tag in the received place? Such as the VLAN 10 trough 802.1Q protocol to pass frames. the 802.1Q will add 802.1q header(tag) and recalculate CRC/FCS like ...
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1answer
1k views

How can I set the switchport's trunk protocol?

How can I set the switchport's trunk protocol? I saw there can use the command to set the trunk mode: SW(config-if)# switch trunk encapsulation ? dot1q isl negotiate but I tried bellow ...
2
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1answer
200 views

trunk between two switches on different network

I have a trunk setup between the 172.16.64.2 and 172.16.128.2 switches, but I can't ping them. I can only ping their default gateways which is their .1 on the router. What am I doing wrong?
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1answer
439 views

Layer 3 switch model 3950 encapsulation

How to ensure trunk link in the switch are using dot1q encapsulation, when dtp (dynamic trunking protocol) is enable along with vtp. I know when manually setting trunk links, you can force the trunk ...
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3answers
66 views

Management switch as a medium only

The main goal is to guarantee communication between CE switches without any PE reconfiguration. Interface GE0/0/1, GE0/0/2, GE0/0/3, GE0/0/4 will be connected to Customer switches. Customer decide ...
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2answers
518 views

Change VLAN id in trunk

I have 3 L3 switches. They're connected to each other with a trunk (in which I need to define the allowed VLAN's). On SW1 I have for example vlan 100. On SW3 I also have vlan 100, but it's another ...
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1answer
634 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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2answers
567 views

spanning tree loop with bpdufilter on acces port but not on trunk?

┌─────┐ ┌─────┐ | A ┼------┼ B | └─────┘ └┬───┬┘ └---┘ <-- loop behold the above drawing. this is a test setup connectin switch A and B, and a test loop A: cisco ...
3
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2answers
9k views

Port channel to two different switches

We had a technician move one of two port channel links from an old switch to a new switch before telling anyone. This left the new and old switch both connected to different links of the same channel ...
2
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1answer
1k views

Really basic SG300 VLAN setup not working

My understanding of VLANs may need improved, but isn't the idea that you can run multiple LANs at layer 2 level over the same router if VLANs are setup correctly on the SG300? If so, I fail to see how ...
3
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1answer
759 views

Add links to a port channel group without downtime

There are two trunk links with the same configuration connecting two switches. Currently they are independent links and one is blocked with spanning-tree. I would like to convert these to a single ...
1
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1answer
141 views

Pinging/ssh-ing into just trunk interface. How is it done? [closed]

I'm a junior network technician and I was tasked at work to do a switch upgrade. The most important part of this task is to set up SSH so we can at least get into the switch remotely configure once ...
1
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1answer
391 views

Sharing VTP Info Between two VTP Servers

Im trying to share info between two vtp servers these vtp server are connected using Etherchannel I have configured both on server mode, using the same domain and password, but the right one is not ...
2
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1answer
131 views

What is a fractional port?

I was reading a product sheet about a Metro-Ethernet backhaul service which mentions, which is described as a mechanism to connect two datacentres within the same region (ie, city) via point-to-point ...