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16 votes
Accepted

Cisco 3750X Power Cable

The cable pictured is a standard: IEC320-C15. The difference is in the temperature rating of the cable. These are rated to 120C, while the "ordinary" ones (IEC320-C13) are 70C. I believe the ...
Ron Trunk's user avatar
  • 67.6k
6 votes

Cisco 3750 - configure to mimic multi location scenario

First, you should probably not use VLAN 1 - it's generally not recommended, or if used, used for network device management traffic only. But, to answer your question, yes, you'd be using inter-vlan ...
Michael D's user avatar
6 votes
Accepted

CDP Native VLAN Mismatch

This happens when something downstream of the switch doesn't understand CDP and mishandles the traffic. So, something is connecting 2/0/5 to 4/0/6; chase the wiring and you'll find it. (someone has a ...
Ricky's user avatar
  • 32.2k
6 votes
Accepted

Cisco 3750G - SSH Diffie Hellman Group 1 SHA1 Error

Your SSH client is saying "we can't agree on the cipher: server wants X but I'm configured not to speak X". This is a completely general SSH problem, not specifically related to this model of switch, ...
jonathanjo's user avatar
  • 16.3k
5 votes
Accepted

Migrating Configuration - 3750G to 3750X

Could this be as simple as copying and pasting "show run?" In general, yes. You will probably need to edit the interfaces because the stackable switches will be something like GigabiteEthernet1/0/1 (...
Ron Maupin's user avatar
  • 99.8k
5 votes

vlan line protocol up/down

In order for a VLAN interface to be up, the VLAN needs to be configured on a access port (Directly connected hosts) or the VLAN needs to be allowed over a trunk. Mind you that the interface or trunk ...
frankguthrie's user avatar
5 votes

Cisco 3750 switch stack with different IOS images

You should really set the IOS version to be the same before adding a switch to the stack. Basically, the switches need to have the same stack protocol version, and only switches with the same IOS ...
Ron Maupin's user avatar
  • 99.8k
5 votes
Accepted

Cisco 3750X Switch stack best practices

I am debating between taking all my servers and putting them on one of the 5 switches, or distributing them over the first few ports of all 5 switches? Best thing to do is distribute them over ...
infra's user avatar
  • 3,128
4 votes

Cisco 3750X Switch stack best practices

If what is important to you with this server is the availability and the uptime of the server, you should distribute the ports across the stack so if a switch goes down, you don't lose connection to ...
bidetzz's user avatar
  • 84
4 votes
Accepted

Scheduled reload Cisco 3750X Slot

You can use the reload at <time> command to schedule a reboot of the whole stack but there is no way that I'm aware of to reload an individual stack member at a specific time, without resorting ...
Jesse P.'s user avatar
  • 4,690
3 votes
Accepted

Moving from 12.x IOS to 15.x IOS - Cisco 3750G

Converting comment to an answer. You can upgrade from version 12.2(35)SE5 directly to the newest IOS version for the switch 3750 series found on Cisco download center. The upgrade process will ...
Cow's user avatar
  • 1,732
2 votes
Accepted

Disable "ip redirect" Cisco 3750

I got a response from Cisco: “Because of hardware limitation, "no ip redirect" does not work in Catalyst 3560 and 3750. If routing is performed on access switch and the next hop of the packet ...
Fanttazio's user avatar
  • 125
2 votes

AAA Authorization

Define the local group for the secondary AAA method for authorization, that way if the servers are down it'll use the local priv level for the user account (make sure it's set to 15 for full access) ...
Fallacy11's user avatar
  • 566
2 votes

Authentication error

After reviewing your configuration it appears that you applied login local only the VTY lines and not the console port. Since you no longer have access to the device you will need to initate a ...
Zack Scaringello's user avatar
2 votes
Accepted

Cisco DAI / arp inspection limit

In the end I made a number of changes to address this issue, in large part thanks to the comments here. I'm working down the broadcast volume so I can set the rate limiting to a reasonable level. ...
Tim Brigham's user avatar
2 votes
Accepted

Static IP assignment 3750X - DHCP Override

This ended up being a configuration issue with the port I was plugged into with my laptop. The configuration on the interface was set to trunking rather than switchport access VLAN10. Once I set the ...
Craken's user avatar
  • 681
1 vote

Cisco 3750G - SSH Diffie Hellman Group 1 SHA1 Error

I had the same issue with my 3750g. I can now log in with: ssh -oKexAlgorithms=+diffie-hellman-group1-sha1 -c aes256-cbc username@switchname
charlesnadeau's user avatar
1 vote

Should portfast be configured on the physical interfaces or on the logical port-channel, or both?

Port-channeling is a way to bypass the topology limitation of spanning-tree allowed to only having a single path. In spanning tree, the logical topology of the data-plane will arrange itself into a ...
Eric Fetty's user avatar
1 vote

Multiple 802.1x clients, single port support on a Cisco 3750 switch?

You need to remove 802.1X authentication from inter-switch links. 802.1X is a port authentication protocol for clients and should be used on edge/access ports only that connect to a single client. If ...
Zac67's user avatar
  • 84.8k
1 vote

Multiple 802.1x clients, single port support on a Cisco 3750 switch?

Any 802 compliant switch will not forward EAPOL. So, the cascaded switch would have to have its own 802.1x client to enable traffic to the upstream switch. (I am unaware of any commercially available ...
Ricky's user avatar
  • 32.2k
1 vote
Accepted

Finding the IP address of a Cisco 3750G

Check for LLDP or CDP advertisements on connected ports (proper tool or packet capturing) or adjacent devices - these usually include the (main) local IP address. Check the DHCP server for a current ...
Zac67's user avatar
  • 84.8k
1 vote

Mixed stack IOS upgrade - Cisco 3750x,3750G

Your process is correct, and assuming you get the same version number for all of them, you should be fine. If you're connected to the stack master, a "dir" should show flash file systems matching ...
Avery Abbott's user avatar
  • 1,793
1 vote

Syslog severity level to 5 + ACL BLOCKED log

Write an EEM script that looks for your syslog message at level 6 and in response emits a syslog message at log 5 or better. Note: I don't know if this works on your device/IOS version. The ...
mere3ortal's user avatar
  • 2,416
1 vote

Syslog severity level to 5 + ACL BLOCKED log

Cisco IOS Configuration Fundamentals Configuration Guide, Release 12.2 Troubleshooting, Fault Management, and Logging You just finish your standard ACL statement with the log keyword. The level of ...
Ronnie Royston's user avatar
1 vote

Syslog severity level to 5 + ACL BLOCKED log

The logging discriminator might be the feature you are looking for here. http://www.cisco.com/c/en/us/td/docs/ios/12_4t/12_4t11/htnmsylg.html#wp1056391 The format of such a discriminator is as ...
surya's user avatar
  • 400
1 vote

3750 failed post. Internal fixed?

Are you sure you are consoled in properly? Cisco will replace the switch provided you are the original purchaser under the Limited lifetime warranty. However, the terms of the LLW state for only 5 ...
Ronnie Royston's user avatar
1 vote

Cisco 3750 switch stack with different IOS images

See Creation and Management of Catalyst 3750 Switch Stacks Software Compatibility Switches with the same major version number but with a different minor version number as the stack master are ...
Ronnie Royston's user avatar
1 vote

How to find the port a device is connected to, based on IP, on a Cisco Catalyst switch

Just telnet yourself into the switch, then unplug the device, then replug it. The switch will write a message which port was down and then up. I hope this helps.
Daniel's user avatar
  • 11
1 vote

How to find the port a device is connected to, based on IP, on a Cisco Catalyst switch

Quickly? Telnet or SSH into the Cisco switch. Type terminal monitor; press enter. Unplug the cable or shut NIC via the OS from the endpoint in question 00:00:47: %LINK-3-UPDOWN: Interface ...
Ronnie Royston's user avatar

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