Switches / Hubs

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A switch is a device that filters and forwards packets of data between LAN segments. Switches operate at the data link layer or the network layer of the Open Systems Interconnection (OSI) Reference Model and therefore support any packet protocol. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched Ethernet LANs. A hub is a connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports; when a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets.

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I'm not sure what I'm doing wrong, but I'm just trying to enable vlan1, as it's administratively down.

I tried no shut vlan1 and no shut vlan 1

Both are not recognized, any thoughts?

vlan
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I'm running older cisco swithces, 2960, 3750, etc...
I configured ntp via:
ntp server 192.5.41.40
Type: clock timezone PST -7 0

But I was thinking, I should use hostname instead, so I tried to use time.google.com, but I keep on getting a "translating" error.

Any ideas how to fix that?
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Is there a Cisco fanless 12 port or 24 port POE switch, gigabit?
I installed a 3750G-24 port switch in my office and the thing is loud, starting to get annoying.

I need at least 9 ports with the uplink, hence the 12 port minimum.
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I have what i think is a basic set up but i am unable to route between vlans on certain switches.  The basic set up is an aruba 3810 that connects to two aruba 2930 switches.  There are several 2930s connected to the 2930s that are connected to the 3810 and the 3810 uplinks across an eline to another site but i am focussing on just the 3 switches; the 3810 and the two 2930s directly connected.  The configs are attached.  I am only working on vlan 5 and 10 right now.  When i connect to the 3810 on vlan 10 i can get to the 3810 IP on vlan 5 but i cant get to either 2930 vlan 5 IPs.  I am expecting the 3810 to route for all these vlans but it doesnt seem to be.  The route table shows that it should.  Ignore the ospf config info as ospf is actually disabled.  This was for testing and potential use later.
5th2930-02Current.txt
5th3810Current.txt
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I'm not sure why, but can someone tell me what I'm doing wrong, I'm trying to setup a cert so I can SSH into the switch, but I keep on getting this invalid input.


Enter configuration commands, one per line.  End with CNTL/Z.
dan_3750G_.40(config)#ip domain-name dan_3750G_.40.com
dan_3750G_.40(config)#crypto key generate rsa
                       ^
% Invalid input detected at '^' marker.

dan_3750G_.40(config)#crypto key generate rsa
                       ^
% Invalid input detected at '^' marker.

dan_3750G_.40(config)#crypto ?
% Unrecognized command
dan_3750G_.40(config)#crypto
                       ^
% Invalid input detected at '^' marker.

dan_3750G_.40(config)#
dan_3750G_.40(config)#


dan_3750G_.40(config)#end
dan_3750G_.40#show ver
Aug 10 20:05:22.226 pst: %SYS-5-CONFIG_I: Configured from console by console
dan_3750G_.40#show ver
Cisco IOS Software, C3750 Software (C3750-IPSERVICES-M), Version 12.2(50)SE5, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Tue 28-Sep-10 12:56 by prod_rel_team
Image text-base: 0x01000000, data-base: 0x02C00000

ROM: Bootstrap program is C3750 boot loader
BOOTLDR: C3750 Boot Loader (C3750-HBOOT-M) Version 12.2(44)SE5, RELEASE SOFTWARE (fc1)

dan_3750G_.40 uptime is 20 minutes
System returned to ROM by power-on
System restarted at 19:44:45 pst Thu Aug 10 2017
System image file is …
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What's to prevent someone from spanning ports on say a Cisco switch and capturing NSX SDN traffic and recreating the traffic it discovers? How is the NSX traffic kept secure from the L2/L3 switches it rides on?

Thanks.
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Dear Experts,

i am looking for a converter with takes 10 gig fibre as input and gives output for RJ45 10 gig. are they available?

if yes can you please send me link to buy online.

i can find on ebay from ethernet to fibre, but i need reverse.

Thanks
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I have two Windows 2012 R2 servers with internal static 192.168.20.x IPs and want to be able to place a switch between them so they can PING to each other, allowing me to plug my static Windows 10 Pro 192.168.20.x IP laptop into the switch so it can also PING these servers

 1. Do I need a managed switch with a static IP in the same 192.168.20.x range and have the switch act as the  192.168.20.1 Gateway ?
 2. If not, what unmanaged switch do you recommend since I was thinking I needed a switch to act as my gateway ?
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Not sure what' i'm doing wrong here as I've done this countless times on older versions.  Have new 2960-x running 15.2,  wanting to use ethernet 1/0/48 as my trunk.   so i do this

switchport mode trunk
switchport trunk allowed vlan 10,19,20,30

but when i sh vlan, none of the vlans show associated with port
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I have multiple cisco switches, from 2960 to 3750, and we are using voip phones that use the same ports as the computers.
So I'm thinking to to leave the computers on the default vlan, which is vlan 1, and have the voip phones on vlan 200 or some other vlan.  As far as I know, to have each port in two separate vlans, I would have to make all ports trunk ports, is there a better or another way than doing that?
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I'm looking online to buy some SFP's for my cisco 3750G and 2960G swithces, does anyone know if these will work?

http://www.prolabs.com/products/datasheets/brocade/E1MG-TX-C.pdf
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Hi experts,
i need some advice. i have about 50 pc's on our company network with 1 file server that these pc's access for AD,DNS, DHCP and our financial application(uses access database). we currently have a 48 port 10/100 switch with 2 gigabit uplink ports as the backbone and then 2 gigabit switches connect to this backbone switch. i was aiming to replace the 10/100mb backbone switch with a full gigabit switch but budget is a problem at the moment. would the following work as a temporary solution for about 3 months: I will install a very entry level 8 port dlink gigabit unmanaged network switch as the backbone, connect my server and links to other switches to this 8 port switch. so from the 8 port switch i will connect all 4 network cards on my server to this switch as well as the link cables from my 3 larger switches. I know this is not the best solution but i just need something that will do the job for a few months? or would this small 8 port switch take too much strain?
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When running the "show version" command on a Cisco switch, one of the switches is always listed with an asterisk at the start of the line.

What does this mean? Based on the output of "show switch" it seems to be indicating which switch is the stack master...?

Example (connected to stack via SSH)...

show version

Switch Ports Model              SW Version            SW Image
------ ----- -----              ----------            ----------
     1 54    WS-C3750X-48P      15.0(2)SE10a          C3750E-IPBASEK9-M
     2 54    WS-C3750X-48P      15.0(2)SE10a          C3750E-IPBASEK9-M
*    3 30    WS-C3750X-24P      15.0(2)SE10a          C3750E-IPBASEK9-M

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show switch

Switch/Stack Mac Address : 0007.7d7f.cb80
                                           H/W   Current
Switch#  Role   Mac Address     Priority Version  State
----------------------------------------------------------
 1       Member 4403.a79c.4500     1      3       Ready
 2       Member 4c4e.353d.b900     1      3       Ready
*3       Master 0007.7d7f.cb80     1      3       Ready

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Hi, I've a Cisco switch on  192.168.1.252 with the following VLANS
VLAN 1 - clients 192.168.1.x range
VLAN 20 - servers 192.168.20.x range

I've also got a procurve switch on 192.168.1.9 with port 1 uplinked to port 2 on the cisco.

Cisco config looks like this:
interface GigabitEthernet1/0/2
 description LAN-CAB02S01
 switchport trunk allowed vlan 1,20
 switchport mode trunk

Procurve looks like this:

trunk 1 Trk1 Trunk
ip default-gateway 192.168.1.254
vlan 1
   name "DEFAULT_VLAN"
   untagged 2-24,Trk1
   ip address 192.168.1.9 255.255.255.0
   exit
vlan 20
   name "Servers"
   no ip address
   exit


When I plug a client into a port on procurve it gets an address on the client LAN which is right but when I configure a client with a 192.168.20.x address i Can't see it.

What am I missing?

Thanks
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We are provisioned Two 2960x Cisco Switches and linked up with a FlexStack Plus cables/modules. All connected devices (e.g. Windows Servers) has two UTPs connecting to the switches, one to switch A and another one to switch B. The switches are implementing Channel Group using LACP where port from Switch A and Port from Switch B are belongs to the same Channel Group for network resilience purpose. Also, we have created TWO VLAN on the switches where each VLAN span across the two switches some network device are belong to VLAN 1 and some are VLAN 2. This is a floor level implementation and we have an uplink router (Core Switch) to route packet between VLANs.

We are planning to add more devices and we are running out of switch ports. Our expansion planning are as follows:

Option 1) Add another two network switches (i.e. 2960x) to the FlexStack cluster and create additional channel groups with switch port from Switch C and Switch D. So that the new devices can connecting to the new Switch C & D while still maintaining the resilience requirement as well as able to communication with the original devices connecting to switch A & B.

Option 2) Option 1 is only feasible if we have enough room to accommodate another two switches on the same rack. If however, we need to put the new two switches on another rack with is around 10-20 meters away still connecting themselves with FlexStack Plus, we are planning to purchase a 10G SFP+ module on the switches and link up Switches A/B …
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bgp
I have the topology shown above. I have configured BGP on R1 which is in AS1 and on R2 which is in AS2
now when I run Show Ip BGP command on each router I get the output shown below. I need an Expert to explain the meaning of the Output  below. especially the lines :
r> 2.2.2.2/32       192.168.12.2             0             0 2 i
*  192.168.12.0     192.168.12.2             0             0 2 i
*>                  0.0.0.0                  0         32768 i




R1#sh ip bgp              
BGP table version is 5, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 1.1.1.1/32       0.0.0.0                  0         32768 i
r> 2.2.2.2/32       192.168.12.2             0             0 2 i
*  192.168.12.0     192.168.12.2             0             0 2 i
*>                  0.0.0.0                  0         32768 i
R1#

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R2#sh ip bgp         
BGP table version is 5, local router ID is 2.2.2.2
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
r> 1.1.1.1/32       192.168.12.1             0             0 1 i
*> 2.2.2.2/32       0.0.0.0                  0         32768 i
*  192.168.12.0     192.168.12.1             0             0 1 i
*>                  0.0.0.0                  0         32768 i
R2#

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Good afternoon Experts,

Our Security Manager asked me to upgrade his existing IP camera network from 10/100 to Gigabit from our Control Room to our guard stations, roughly 150 meters away. The existing network we have been using is 2 Comnet devices, model CNFE6+2USPOE. More details on this device here:

http://www.comnet.net/comnet-products/ethernet/self-managed-switches/cnfe62uspoe.html

I decided to purchase 2 Netgear, model ProSafe-GS110TP:

https://www.netgear.com/support/product/GS510TPP.aspx

Connected with TrendNET TEG-MGBSX SFP Modules

https://www.trendnet.com/products/proddetail?prod=200_TEG-MGBSX


My issue is that I get no link light when I set up a switches in both locations. I have tested the units side by side and it all works, but for some reason when I get them set up in their specific location I no longer get link lights. I'm using the existing fiber run that the Comnet devices are on, and have confirmed it's 50/125 fiber, and I've tested the new short fiber cables we bought and they work as well. The TrendNET SFP modules should be rated at 550 meters.

In my other experience things like this just fire up, then you make sure the VLAN's are correct, but in this case I get link down in the Netgear GUI and obviously no sweet flashing green light.

Am I missing the forest through the trees here?

Thank you for any guidance.
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Hi All

Can I have you're help with the all commands needed for a single switch port to assign this up address.

172.16.0.10/30 255.255.255.252

Appreciate you all your help thank you
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Hello experts. I am trying to setup a VLAN in a test environment and I am not able to get it to work so far. I have searched this board and researched online but just can't seem to get it to work.

Right now I have two Comcast internet circuits coming into a peplink balance 20 (will be upgraded to the balance 305) I have one cat 6 patch cable going from the router lan port 1 to Switch 1, port 1. I have a total of 5 sg200 switches, all connected by 4 port LAGS and fiber.

I want to have 3 VLANS. On the peplink under LAN--->network settings I created the VLANS as 10 with an IP of 192.168.10.1 with DHCP enabled for 192.168.10.2 - 192.168.10.250, VLAN 20 as 192.168.20.1, VLAN 30 as 192.168.30.1 all with DHCP enabled. Under LAN--> port settings I have port 1 set to trunk and tagged the 3 VLANS.

I have the VLANS setup on all of the switches. On Switch 1, port 1 where the router is connected I have it set to tag the 3 VLANS I created.

On Switch 1, port 5 I have a laptop connected to test. I have that port set to access and VLAN1 to exclude, VLAN10 as untagged. From this point I am unable to get a dhcp address and if I enter a static ip I am unable to get internet access.

Is everything correctly configured so far? Right now everything is operating from the one switch. I haven't tried other ports on other switches.

What do I configure the LAGs as?

Any help will be VERY much appreciated!

Thanks in advanced,
CJ
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Dear, we found an old switch Cisco 2960 in warehouse, it still works when we plug in the power but we 'd like to make sure it will not suddenly die. So how can I check the health of that switch? Can anyone please suggest some commands to check:
- When was it used for the first time?
- How long can it be used?

We want to utilize it for a new project so please help! Many thanks!
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I have an unmanaged Cisco/Linksys SG 100-24 switch. It has gigabit capibility.  My servers are connected to this switch at 1 GB and it's on auto detect however my PC's which are capible of gigabit are only connected a 100 mbs.  I've tried to make them 1000 full duplix but I'm only seeing 100.
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Hello - we have a Windows Server 2012 that has 2 NICs that are bonded into a Team Nic connection.  It was working for a short time, where it was successfully able to access the Internet and network resources, but then a yellow exclamation mark appeared on the NIC icon in the service tray and it stopped getting out to the Internet.   I was also not able to RDP to it (strangely however, my cohort was able to remote to it).  so I went on to the machine's console and "Diagnosed" it.  it wanted to remove the NIC teaming and when both adapters are separated, it works - meaning I am able to assign static addresses to the adapters and it connects fine.  I forgot to mention that at first, when I diagnosed the Team connection, it wanted to switch it to DHCP and then the yellow mark went away.  I was not able to make it a STATIC IP assigned - it only takes DHCP.  But now that the NICs are separated again, I can assign static IPs. Looking for some insight.
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Dear Zealots, is there any method to observe, monitor the traffic from one (or multiple) IP address (es) to a IP address?
We are using Cisco Router 3925, Switch 3560, 3750, 2960
Many thanks in advance,
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Hello,

All the trunk port needs  be connected using cross over cable or depends on the switch? IF MDI is enabled then don't need it ?
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How to block unmanaged switches from network. I have already apply BBDU Guard on interface but where unmanaged switches attached port will not block. and in show spanning-tree interface detail command no BpDU received. So please help is required for block unmaanged switches fron network. Other than port security please
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Switches / Hubs

20K

Solutions

17K

Contributors

A switch is a device that filters and forwards packets of data between LAN segments. Switches operate at the data link layer or the network layer of the Open Systems Interconnection (OSI) Reference Model and therefore support any packet protocol. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched Ethernet LANs. A hub is a connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports; when a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets.