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1

Configuring a single router with OSPF does nothing but waste CPU cycles on a router. Routing protocols do not route, they exchange routing information with other routers running the same routing protocol. Also, if all you have is a single network, then routing is completely unnecessary because routers route packets between networks, not from a network back ...


6

A layer-2 switch does not look at the layer-3 IP address on a packet to switch the layer-2 frames, and it only uses the MAC addresses on the frames for switching. The layer-3 interface on the switch is for switch management. It is like another host on the LAN, and it will not update its ARP table unless it communicates with a host at layer-3. Switches use a ...


2

Don't overthink, it's fairly simple. When a frame arrives at an L3 switch, it is forwarded according to its destination MAC address. With normal L2 switching, the destination is a node off one of the switch ports. If that destination MAC is the L3 switch itself (more precisely, one of its L3/routing/SVI interfaces), the encapsulated IP packet is passed to ...


4

There are multiple types of Ethernet frames. The common ones today are Ethernet-II and 802.3 ethernet. They both start the same but diverge when they get to the ethertype/length field. From Wikipedia "Ethernet frame" The "Ethertype or length" field is how you tell whether it is EthernetII or 802.3. If the field is less than 1500 then it means that the ...


3

An EtherType/Length value up to 1500 (0x05dc) indicates the frame's payload length. The values 1501-1535 (0x05dd-0x05ff) are undefined, real Ethertype values start at 1536 (0x600). The receiving switch is probably ignoring the rest of the frame and since the supposed FCS doesn't match, it drops the error frame. You'll need to use a larger value and take ...


2

Do Cisco SG300 switches perform CRC error correction? No, nor do any other Ethernet switches.[*] The Ethernet frame's frame check sequence algorithm cannot correct errors, it can only detect them - as long as multiple bit errors don't cancel each other out. Erroneous frames are dropped. FCS errors do not cause link loss on the physical layer at any time. ...


0

Since it is not required to have a trunk link end-to-end, you can use different VLAN ids instead of different physical switches. I mean you can use L2SW2 with a VLAN ID 100 between laptop and router. (2 Ports on the switch are members of VLAN 100). L2SW2 with a VLAN ID 101 between two routers. (2 Ports on the switch are members of VLAN 101). and the same ...


0

19200 Bd 8N1 (8 data bits, no parity, 1 stop bit) seems OK. Make sure you've selected the correct serial interface in the terminal software got a suitable console cable deactivated hardware flow control hit [Return] a couple of times If the switch is configured for a specific speed you'll have to match that.


1

In GNS3, switches are basic devices that need no configuration. As @zac67 points out, you still need to configure routing (static or dynamic) between R1 and R2.


1

Basic switches are entirely self-learning (bridges), they don't need any configuration. Managed switches should be configured to require a password for all management interfaces (SSH, telnet, web, SNMP, ...). All more advanced features like STP, VLANs, LAG, port-level authentication, ACLs and of course L3 switching require configuration as well. Your ...


1

Holding the button in for 10 seconds or more is basically the same thing as performing a factory reset. I would hope somebody has the configuration backed up somewhere and can easily dump it back on the switch.


0

Find the 100% security is basically impossible, however there is something that could help you that is the interface isolation. This means that you use network cards (interfaces) specific for user data, management and others, and you don't mix them. This is not possible all times but prevents issues such as the management of the VLANs as well as complex ...


3

Putting aside the impossibility of 100% security, your plan seems sound. Of course, everything depends on the policies on the firewall. To answer your specific questions, yes, the switch ports to the firewall are promiscuous, and configuring a VLAN on (most) firewalls creates a separate logical interface.


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I want devices connected to VLAN 10 to have no ability to communicate with the internet or any other VLANs on the switch. Simply do not connect a router to that VLAN. Each VLAN is a contained link-layer segment and without a router, that VLAN can't communicate with anything outside. You can still trunk the VLAN across multiple switches without a problem.


0

So I would expect the switch to discard the incoming vlan tag 600 and forward packets internally to all ports assigned to vlan 2. That's not the way it works. When an incoming frame is associated with VLAN 600 it stays within that VLAN (you could route the encapsulated packet elsewhere though). So, you need to make both the ISP facing port and the firewall ...


3

Yes. You don’t even need a trunk. If all ports on both switches are access ports on Vlan 3, then the port connecting the two switches are on Vlan 3 and both switches form one broadcast domain on that Vlan. If switches are unmanaged then all ports would be on the one Vlan and the number is irrelevant. A couple helpful details: Access ports to end hosts or ...


2

Without VLANs, connected switches form a single broadcast domain - that is exactly what you need for an IP subnet. Just connect away. VLANs allow you to split (partition) a shared switched infrastructure into distinct broadcast domains - ideally suited for multiple IP subnets. In order to connect multiple VLANs across a single link you'd need a trunk, ...


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