Questions tagged [trunk]
For questions about trunks, layer-2 links across which traffic for multiple VLANs travel.
184
questions
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51
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Non VLAN Tagged Traffic Not Going Through Trunk Between Cisco Switches
Good day all.
I am running through a packet tracer exercise and am stuck on where to go next. Forgive me if I am missing something obvious, I have not touched any cisco networking or networking in ...
0
votes
1
answer
53
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Switch Configuration - Change the trunk allow VLAN
May i know any service interruption if i issue the command on changing the trunk allowed vlan on both end:
switchport trunk allowed vlan 10, 20, 30 to switchport trunk allow vlan 10, 20, 30, 40
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1
vote
1
answer
95
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Why its need to use trunking when using etherchannel? [duplicate]
what's the reason to use trunking by using the 2 below commands:
switchport trunk encap dot1q
change the mode to trunk
between EtherChannel ports
the second question why to make native vlan under ...
- 11
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0
answers
209
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Cannot tag an interface for a specific VLAN : % Error: Tagged flag mis-match Te 0/3
I trying to tag an interface for a specific VLAN on a Dell S4810 :
S4810#show run int ten 0/3
!
interface TenGigabitEthernet 0/3
no ip address
mtu 12000
switchport
flowcontrol rx on tx on
no ...
- 135
0
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1
answer
30
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what is the relation between DTP and VTP?
the ideas behind VTP & DTP are different, then why do we need to make sure that the VTP domain on both sides is the same otherwise the DTP will not work?
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1
vote
0
answers
101
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Can't Pass 1 VLAN Through Trunk
I have 2 Cisco switches running IOS with VLANS 20,30,40,50. On SWITCH1 I have servers on Ports 1,2&3 on VLAN 30. I also have a laptop on port 5 on the same VLAN 30 and can ping the servers. They ...
- 461
0
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1
answer
85
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No Ping Through Cisco Trunks
I am trying to ping on my management VLAN across a trunk between 2 Cisco switches. Both switches have the following configs
interface TenGigabitEthernt1/1/1
switchport trunk native vlan 5
switchport ...
- 461
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votes
4
answers
1k
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Communication between different VLANs
In my previous understanding, there is no way to communicate between two VLANs using only layer 2.
After all, this is the purpose of having VLAN.
I found a forum that claims the following.
1.VLANs can ...
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1
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0
answers
654
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Nexus 7706 - switchport trunk allowed vlan not working - all VLANs are being allowed
I noticed that my two Nexus 7706 do not limit the trunk VLANs to what switchport trunk allowed vlan is set to.
Sample configuration:
interface Ethernet1/15
switchport
switchport mode trunk
...
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2
votes
1
answer
455
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How do you drop (or ignore or filter) all untagged traffic on an 802.1q trunk port?
This answer says "[a] trunk has optionally one untagged VLAN and many tagged VLANS."
I always thought specifying switchport mode trunk would drop untagged frames at that port, but that ...
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3
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361
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What does `switchport trunk native <n>` do when in `switchport mode trunk`?
According to this article Cisco recommends VLAN 99 for the "native VLAN".
But what is the point when operating under switchport mode trunk?
Doesn't switchport mode trunk filter all tagged ...
- 157
-1
votes
1
answer
63
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aggregating Cisco 2960 ports with Cisco 3850
I'm new to networking. I have two switches: Cisco 2960 & Cisco 3850. I want to connect 4 Trunk ports of these switches to each other. Since Cisco 2960 port speed is 1G and Cisco 3850 is 10G, I ...
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1
vote
1
answer
447
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VLAN trunking - how to ping PC4 from PC1?
I'm still a beginner with VLANs and trunking, and I'm trying to get this topology working. Specifically, I am unable to ping PC4 (10.0.10.11/32) from PC1 (10.0.10.10/32), despite both of them being on ...
- 125
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1
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60
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How Switchport Trunk work?
I the scenario below;
I can sniff the traffic between Win7 and UbuntuSrvr on Line A
but this is cannot be done on Line B
Note: ports are on trunk mode.
Why this is happening??
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2
votes
1
answer
51
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Access and Trunk Port [duplicate]
I have an access port that I'm trying to change to a trunk port. So, while I'm on the interface I
want to change and do:
switchport mode trunk
switchport trunk allowed vlan x
a show run command then ...
- 123
1
vote
1
answer
972
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Need help with HPE tagging and hybrid-mode port
At my office I have two switches. SW-1 (HP-V1910-48G) is the switch my desktops are connected to, and SW-2 (HPE-1920 JG927A) is where my server rack with my dhcp and default gateway is connected. ...
1
vote
1
answer
68
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Access layer switches uplink mode
We have core, distribution and access layer switches.
the switches in access layer connect several workstations on VLAN 20 only.
we have DHCP server on VLAN 1 but is on another switch with all servers....
- 113
2
votes
1
answer
431
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Why I can't ping my switch Vlan99?
In the following network, I have configured every device but somehow I can't ping my Customer-PC and Technical-PC to PasirGudang-SW and Segamat-SW.
The PCs can ping the other ip address just fine ...
- 21
0
votes
1
answer
193
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Do unicast frames get sent to all switches associated with the target VLAN?
If a network topology has a VLAN which spans multiple switches, what happens if a frame is sent to a MAC address that is connected to the source device's "home" switch? By that I mean if a ...
- 101
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0
answers
201
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Dropping packets when mirroring a switch trunk port
I'm building a test lab to support a networking monitoring application I'm developing.
I have written a simple UDP packet generator and receiver, and I use iperf3 to create some bulk background ...
0
votes
1
answer
1k
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pfSense - Trunking VLANs on LAGG vs. individual links
We are a small business. I am running pfSense on a decommissioned developer's PC. We have also a Cisco SG 300 L3 switch, capable of VLANs and LAGG (link aggregation).
I am going to do RoaS (router on ...
- 103
2
votes
2
answers
522
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Connecting two HP 2910al Switches using SFP to get 2Gb/s speed
I would like to Connect my two HP 2910al switches using SFPs to get a maximum of 2G links.
is this possible, and how?
I want to make both of them to use the IP address (ex 192.168.2.xxx).
I have the ...
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0
votes
1
answer
873
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Connecting two Stacked Aruba 2930M Switch with third one using LACP
In the skit, I would like to connect the two Stacked switches with a third one
using the SFPs+ Modules and therefore I need to configure the LACP for them.
How can I configure the LACP on both the ...
- 27
2
votes
1
answer
457
views
Port only in trunk mode vs encapsulating the frame
A network with 2 switches, each switch has 2 vlan, one called vlan 10 and another vlan 20.
A port-channel with 2 uplinks (trunk). Why in a layer 2 scenario I don't need to configure the trunks with ...
- 37
2
votes
2
answers
3k
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 ...
0
votes
2
answers
4k
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 ...
1
vote
1
answer
215
views
VLAN not working in ComNet switch [closed]
I'm trying to configure VLANs with 3 switches ComNet (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 didn'...
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2
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1k
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How to monitor vlan using SNMP?
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 ? ...
1
vote
2
answers
326
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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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3
votes
1
answer
50k
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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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0
votes
1
answer
477
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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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1
answer
1k
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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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2
answers
195
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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?
1
vote
2
answers
885
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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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votes
3
answers
834
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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 ...
- 103
0
votes
1
answer
1k
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 ...
- 219
0
votes
2
answers
318
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 ...
- 170
3
votes
1
answer
369
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 ...
- 145
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votes
2
answers
579
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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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1
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1
answer
208
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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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1
vote
1
answer
574
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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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6
votes
2
answers
3k
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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 ...
0
votes
1
answer
141
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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 ...
0
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1
answer
147
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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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vote
1
answer
7k
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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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4
answers
187
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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 ...
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4
votes
1
answer
1k
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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 ...
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4
votes
1
answer
7k
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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:
...
- 4,371
5
votes
2
answers
7k
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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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4
votes
4
answers
2k
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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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