Cisco TRUNK port “Monitoring” state 19 Nov 2024, 11:51 pm

VERIFY: show running-config | s monitor session
running-config must have the global config lines:
monitor session 1 source interface <Gi1/0/1>
monitor session 1 destination interface <Gi1/0/>

switch# show monitor session ?

switch# show monitor session ALL

switch# config t
switch(config)# no monitor session <#>
switch(config)# end
switch# copy run start

Viewing CRC Error Counters 30 Sep 2024, 10:52 pm

To troubleshoot physical layer issues within the fabric

Switch# show interface <ethernet 1/1>
.....
RX
0 unicast packets 200563 multicast packets 0 broadcast packets
200563 input packets 27949761 bytes
0 jumbo packets 0 storm suppression bytes
0 runts 0 giants 0 CRC 0 Stomped CRC 0 no buffer
0 input error 0 short frame 0 overrun 0 underrun 0 ignored

Reference

Viewing CRC Error Counters (cisco.com)

Cisco Catalyst Base-Config 18 Sep 2024, 6:22 pm

conf t
!
no ip domain lookup
no system ignore startupconfig switch all
!
hostname <deviceName>
ip domain name <urDomain.network>
username <localUSER> priv <15> secret <superSECUREpassL!ke12345>
line vty 0 4
   login local
   logg sync
line con 0
   login local
   logg sync
!
! --- crypto key zeroize rsa
! --- yes
crypto key generate rsa general-key modulus 2024 label SSH
!
! --- for REACHABILITY choose between L2 or L3---
! L2 configuration
no ip routing
ip default-gateway <ip.ad.dr.ess>
! or
! L3 configuration
ip routing
ip route 0.0.0.0   0.0.0.0   <enc.ip.ad.dr>
int XX/XX
   no swithport
   ip address <ip.ad.dr.ess>   <sub.net.ma.sk>
   no shut
!
! --- defining VLANs
vlan <MGMT#>
   name MANAGEMENT
interface vlan <MGMT#>
   ip address <ip.ad.dr.ess>   <sub.net.ma.sk>
   no shut
! -=-=- !
vlan <USER#>
   name USER-ACCESS
interface vlan USER#>
   ip address <ip.ad.dr.ess>   <sub.net.ma.sk>
   no shut
!
vlan <VoIP#>
   name VoIP-ACCESS
interface vlan <VoIP#>
   ip address <ip.ad.dr.ess>   <sub.net.ma.sk>
   no shut
! -=-=- !
vlan <PRNTER#>
   name PRINTER-ACCESS
interface vlan <PRINTER#>
   ip address <ip.ad.dr.ess>   <sub.net.ma.sk>
   no shut
!
!
! --- defining TRUNKs
interface XX/XX
   switchport mode trunk
   duplex full
!
!
! --- defining ACCESS/VOICE PORTs
interface range <xx/begPort> - <endPort>
   switchport mode access
   switchport access vlan <usr/prn>
   switchport voice vlan <VoIP#>
   ! sw port-security max ##
   ! sw port-security mac-address sticky
   ! sw port-security
   ! spanning-tree portfast
!

C9300 not saving the config after a reboot 18 Sep 2024, 5:37 pm

After configuring the C9300 switch, can successfully save the config using “write mem” or “copy run start”, but after a reboot switch will go back to factory-default configuration.

This happens when there was password recovery and the command “Switch: SWITCH_IGNORE_STARTUP_CFG=1” was ran.

Fix it by running the following commands:

! tested successfully on ver. 17.x.x
(config)# no system ignore startupconfig switch all
! command below only works on ver 16.x.x or older
(config)# switch all config-register 0x102
# copy run start
# reload

Reference:s

Understand Configuration Register Usage on all Routers – Cisco

MS Outlook — Restore the Unread Mail folder 23 Jul 2024, 11:01 pm

If Microsoft Outlook UNREAD folder is not visible, add it back using the following steps:

1. Open Outlook app
2. Click on Folder from the menu bar
3. Select “New Search Folder”
   • Then select “Unread mail” under the Reading Mail group

4. Right click on the “Unread Mail” or highlight the folder, then “Add to Favorites”.

Catalyst 9K – Advantage vs. Essentials 14 Mar 2024, 1:36 pm

Reference: https://www.cisco.com/c/dam/global/da_dk/assets/training/seminaria-materials/Licenses-Networking-for-everybody-with-DNA.pdf

Power Cords IEC C15 type and NEMA 5-15 14 Mar 2024, 2:36 am

NEMA 5-15P vs 5-15R

The first number represents the voltage level, while the second number is for the amperage rating.

“P” = Plugs (male) “R” = Receptacle (Female)

SF-81 (C14) to SF-52 (NEMA 5-15R) Cable

NEMA 5-15R to C14 Power Plug Adapter

References:

• Power Connectors – Overview (youtube.com)
• What is a NEMA 5-15 Plug? — Lectron EV (ev-lectron.com)
• NEMA Plug Charts | Americord | NEMA Configurations
• World plugs (iec.ch)

Using iPerf to Test Network Banthwidth 11 Mar 2024, 2:05 pm

iPerf is a tool to maximum achievable bandwidth on IP networks. By default iPerf benchmark will run for 20 seconds.

cli:\> iperf -c <se.rv.er.ip> -w <window-size> -p <port>
c:\ iperf -c <aaa.bbb.ccc.ddd> -w 2048 -p 2525

iPerf3.exe -c <aaa.bbb.ccc.ddd> -p 7575 -bidir

iPerf3 -c <aaa.bbb.ccc.ddd> -w 10mB --omit 1

iperf -s -u -i 1s

References:

• iPerf – iPerf3 and iPerf2 user documentation
• Iperf cheat sheet | JamesCoyle.net Limited
• https://www.dell.com/support/kbdoc/en-us/000139427/how-to-test-available-network-bandwidth-using-iperf

Link Layer Discovery Protocol (LLDP) 11 Mar 2024, 1:46 pm

By default LLDP is disabled on all Cisco devices. To use LLDP on a Cisco device, you need to globally enable LLDP and allow the interface to transmit/receive LLDP packets.
From <https://www.grandmetric.com/knowledge-base/design_and_configure/lldp-configuration-example-cisco/>

To GLOBALLY enable & disable LLDP:
	Switch# configure terminal
	Switch(config)# lldp run
	Or
	Switch(config)# no lldp run

To activate LLDP to transmit/receive on the INTERFACE:
	Switch# configure terminal
	Switch(config)# interface GigabitEthernet 1/1
	Switch(config-if)# lldp transmit
	Switch(config-if)# lldp receive
	Switch(config-if)# end

To transmit LLDP packets only:
	Switch# configure terminal
	Switch(config)# no lldp receive

To configure LLDP frequency reorting:
	Switch# configure terminal
	Switch(config)# lldp holdtime 120
	Switch(config)# lldp reinit 2
Switch(config)# lldp timer 30

To Verify/clear syntax: 
	switch# show lldp
	switch# show lldp traffic
	switch# show lldp entry entry
	switch# show lldp interface interface-id
	switch# show lldp neighbors interface-id
	switch# show lldp errors
	switch(config-if)# show lldp interface <ethernet G1//1/>
	switch# clear lldp counters
	switch# clear lldp table
From <https://ipcisco.com/lesson/lldp-configuration-on-cisco-ios/> 

References:

• LLDP configuration example (Cisco)
  https://www.grandmetric.com/knowledge-base/design_and_configure/lldp-configuration-example-cisco/
• Cisco Nexus 9000 Series NX-OS System Management Configuration Guide, Release 10.1(x)
  https://www.cisco.com/c/en/us/td/docs/dcn/nx-os/nexus9000/101x/configuration/system-management/cisco-nexus-9000-series-nx-os-system-management-configuration-guide-101x/m-configuring-lldp.html
• LLDP Configuration on Cisco IOS
  https://ipcisco.com/lesson/lldp-configuration-on-cisco-ios/

CLI — RUN a batch file with MINIMIZED window 7 Mar 2024, 3:56 pm

SYNTAX

cmd.exe /c start /min myfile.bat ^& exit

cmd /c start notepad

cmd /c start /min cmd /k notepad

• the *.exe is needed as start is no windows command that can be executed outside a batch
• /c = exit after the start is finished
• the ^& exit part ensures that the window closes even if the batch does not end with exit

Running PuTTY
@echo off
cmd /c start <path:\putty.exe> <username>@server -P <port#> ^& exit

example: 
cmd /c start c:\Users\User1\Desktop\putty.exe user@aa.bb.cc.dd -P 22 ^& exit
cmd /c start putty.exe user1@aa.bb.cc.dd -P 22 ^& exit

References

• How to Run a Batch File or Another File Minimized (computerhope.com)
• windows – How to run the command prompt minimized? – Super User