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

1
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2answers
26 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
votes
2answers
42 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 ...
0
votes
1answer
37 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 ...
1
vote
1answer
48 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?
1
vote
1answer
46 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 ...
0
votes
3answers
51 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 ...
2
votes
2answers
72 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 ...
1
vote
1answer
124 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 ...
1
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2answers
135 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 ...
1
vote
2answers
1k 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
votes
1answer
217 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 ...
2
votes
1answer
94 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
vote
1answer
51 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 ...
0
votes
0answers
74 views

ROAS driving me crazy

Can anyone else help me please! I have all clients connecting to a L2 switch, these trunk (etherchannel) into another L2 switch, which then trunk (etherchannel) into another L2 switch (core) and these ...
1
vote
1answer
55 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 ...
3
votes
1answer
74 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 ...
1
vote
1answer
173 views

Trunk Ports only Allowing Native VLAN?

I'm trying to set up a guest network. The native VLAN for our switches (all Cisco Catalyst switches) was never changed away from 1 (untagged). I've created VLAN 20 to use for the guest network. ...
0
votes
1answer
134 views

Vlan trunking and routing

I need help with something. I have this topology and i want to know how to go about configuring it: I have 4 vlans and 10 hosts and 6 switches I have created 4 vlans vlan 2- Admin Vlan 3 - ...
4
votes
2answers
85 views

increasing bandwidth between two Cisco switches?

2 Cisco 3750 switches are connected via port 22(Trunk). First switch consists of 3 VLANs(each vlan have 7 ports such as 1-7,8-14,15-21) and 2nd switch consists of 2 VLANs. what solution can i use to ...
3
votes
1answer
222 views

Trunk on the outside ASA interface

I have a topology as in the picture. It is designed to be a factory network. 2 ASAs in a failover cluster border the whole LAN. And it is pretty much clear how to configure them: outside interface to ...
4
votes
2answers
1k views

The best way to understand Vlans?

Every time i try reading about the configuration of a device and adding it to the network, i always face a problem. The problem is basically am not able to understand Vlan's, and how for example some ...
1
vote
0answers
395 views

Configure pfSense VLAN Trunk

I have setup a pfSense box as a transparent firewall between my Cisco router and first Cisco switch: CISCO ROUTER - 10.10.1.253 ↓ PFSENSE - OPT1 BRIDGE - 10.10.1.252 ↓ CISCO CORE SWITCH - 10.10.1.250 ...
1
vote
1answer
67 views

VLAN creation with trunk port configuration

I have three switches and I configured VLAN with trunk on those switches but my requirement is VLAN 1, VLAN 2, VLAN 3 has to be configured on Switch 1 and Switch 3, but I don't need VLAN 2 ...
1
vote
1answer
58 views

Trunk method on cisco switch

I knew about trunk concept but I don't know about connecting cables method. If we have 8 switches to connect trunk cables across those 8 switches, any methods or rules?
2
votes
2answers
169 views

Trunking across different switch makes

I have a Dell N3132PX running 6 different VLANs. (192.xxx.xxx.10) VLAN 2 is my management VLAN for my switches. VLAN 3 is my DHCP network running production level for users. Port 25 (Untagged) VLAN ...
1
vote
3answers
720 views

Native VLAN question

Regarding the Native VLAN role (example, VLAN 1 by default for Cisco), we often can read that: The untagged frames arriving on a trunk port, are "put" in the Native VLAN The untagged frames arriving ...
1
vote
1answer
98 views

10Gbe Network Setup, Freenas Backup and File Sharing

I have a small office network that has: ISP: 100Mbps up / 100Mbps down Firebox M200 (Firewall/Router) 8 x 1Gbe ports / 3.2Gbps Firewall throughput Cisco SG200 1Gbe Switch / 26 port *Planned 10Gbe ...
3
votes
1answer
336 views

Setting a loopback/management address through a layer 2 trunk

We have two EX4200 switches in the following configuration: Router (.1)=====static route=====(.2) EX_01========trunk========EX_02 I want to configure a loopback or management interface on EX_02. ...
1
vote
1answer
52 views

Need clarification on some Cisco configurations

Here is the situation : I have an HP server with 2 network interfaces linked to a Cisco switch. I want to configure the switch to accept the NIC teaming of the server. I have always believed that the ...
5
votes
1answer
1k views

Cisco iOS SNMP OID for Vlan on Port

I am working on setting up SNMP monitoring for our internal switched network in Zabbix. I have everything working now, but the template I am using discovers all ports on the switch, and I really only ...
1
vote
2answers
851 views

Can default vlan 1 traffic goes to native vlan 2?

I have 2 switches running on 802.1Q trunking mode. On both switches the default vlan is 1. If I were to configure the native vlan to 2, can vlan 1 traffic still travel from switch to switch? After I ...
1
vote
1answer
123 views

Not able to get a trunk between router and distribution switch to succeed

I couldn't get a successful ping from the router to the distribution switch Distribution Switch Dist_Switch#sh ru Dist_Switch#sh running-config Building configuration... ...
0
votes
2answers
168 views

Feeling lost troubleshooting Trunk and STP configurations on Packet Tracer

I couldn't identify the mistake or what I have missing in the configuration on this network, if anyone of you is welling to check it out this is the link PacketTracerFile I could not ping from any PC ...
0
votes
1answer
232 views

L2 transparent firewall between router and switch running 802.1Q trunk mode

Router port facing to Core switch is running trunk mode allowed vlan 200 & 300. I am placing a firewall between the trunk connection. Can I set the firewall as L2 transparent mode or I need to ...
2
votes
3answers
393 views

Force VLAN traffic through specified interfaces

I have two VLANs, VLAN1 for "clients" and VLAN2 for (web)servers. Both VLANs have two ports in etherchannel (one Cisco switch). I would like to put transparent (WAF) device in bridge mode between the ...
0
votes
1answer
358 views

Help with Native Vlan mismatch error

I'm pretty new to networking. I'm working on creating some vlans, assigning them some ports, and then trying to configure one of those vlans as the native vlan. here's what I have done. Switch(config)...
1
vote
1answer
53 views

Bridge traffic forwarding in vlans

on a trunk, switch A having, say vlan 10 allowed and the other switch B does not. Switch B doesn't even know about that vlan. How does switch A behave in forwarding broadcasts in vlan 10? Will frames ...
1
vote
3answers
1k views

Connecting two switches with an access mode port

I manage a switch, and I saw that on one interface there were 19 different MAC addresses, all of them on the same VLAN, so I guessed that there was a switch connected to that interface. Since all MAC ...
1
vote
1answer
45 views

Create a trunk to a device with two NICs but one MAC address

I have a Linux device with two NICs, but they seem to share one MAC address. I want to configure a redundant network connection to a switch stack. Whenever I restart the end device, it is shutting ...
2
votes
1answer
177 views

Switchport negotiation between trunk and dynamic desirable

If two switches are connected, one with switchport mode trunk and the other with switchport mode dynamic desirable, will both switches form an operational trunk?
1
vote
2answers
352 views

Why is my inter vlan trunk routing not working?

I'm using packet tracer. I have the following configuration : On switch 2950-24 VLAN 99 . interface assigned to it is fa 0/1 PC 1 has ip 10.10.10.2 with default gateway 10.10.10.3. PC 1 is ...
1
vote
2answers
10k views

What is difference between standard VLAN extended VLAN?

I know that the range of standard VLAN is 1-1005 and in extended VLAN the range is 1-4094. But is just range is the difference?
3
votes
2answers
264 views

necessary and sufficient condition for vlans to communicate together

Let's say I know my switches configurations, for each, I know what port are configured in access, what port are in trunk, and what vlan is on a port. For each device. I want to group vlan that can ...
1
vote
1answer
875 views

Will DTP always use the native VLAN or always VLAN 1?

I'm having trouble understanding whether DTP will always use the native VLAN, even if it's configured to be non-default, or if it will use VLAN 1 in any case. For example, if you configured VLAN 50 to ...
3
votes
2answers
80 views

What happend when you set a trunk against an Access

I'm wondering what would happen in my network in the following configuration: on switch1 -> interface1 in mode access, vlan4 on switch2 -> interfaceA in mode trunk, vlan4 and vlan8 switch1 is ...
0
votes
1answer
649 views

Is DTP enabled by default on the newest Cisco devices?

Is DTP (Dynamic Trunking Protocol) enabled by default on the newest Cisco devices? I have been using Cisco 2960 switches and DTP is enabled by default. I was wondering if this was the same for the ...
2
votes
3answers
2k views

Best practice for connecting router to switch? (re: VLANs and multiple ports)

When using multiple VLANs, what is the best practice for connecting a router to a switch? For example, I can use one single port (and one cable) between the switch and router and set it up as a VLAN ...
2
votes
2answers
6k views

What is the purpose of a trunk port in a network switch? [closed]

I have recently taken over responsibility of the management of the switches in my apartment complex. We two switches, 1 and 2, the fiber connection to the internet is connected to switch 1. Switch 2 ...
2
votes
2answers
2k views

Aren't Switch Access ports tagged?

I've read where frames are tagged only when going over a trunk and that Access ports do not tag frames. But don't Access ports actually tag frames? When I configure a particular port to be in a ...
7
votes
3answers
579 views

New VLAN across multiple Cisco switches

I have setup a new VLAN on my corporate network for use for guests only. I am trying to setup a guest WiFi service and keep all of the traffic separate from the business traffic. So far I have ...