I picked up a used Dell S4820T 10GBase-T switch for a work project recently. Here are the steps I took to wipe, upgrade, and perform the initial configuration.
Serial Console
Before doing anything with the switch, it’s worth investing in an RJ45 to USB (or USB-C) serial cable. They can be found for $10-15 in the usual places. In my case, I could not login to the switch over the network when I received it, so this was the only way to perform the initial configuration.
The cable I found is called a “USB-C Cisco Console Cable, OIKWAN 6ft USB Type C to RJ45 Serial Adapter.” Here’s the output from dmesg:
[27278.597120] usb 1-1.3: new full-speed USB device number 4 using ehci-pci
[27278.717078] usb 1-1.3: New USB device found, idVendor=0403, idProduct=6001, bcdDevice= 6.00
[27278.717111] usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[27278.717117] usb 1-1.3: Product: FT232R USB UART
[27278.717121] usb 1-1.3: Manufacturer: FTDI
[27278.717125] usb 1-1.3: SerialNumber: A9DFE78I
[27278.741228] usbcore: registered new interface driver usbserial_generic
[27278.741242] usbserial: USB Serial support registered for generic
[27278.745161] usbcore: registered new interface driver ftdi_sio
[27278.745175] usbserial: USB Serial support registered for FTDI USB Serial Device
[27278.745232] ftdi_sio 1-1.3:1.0: FTDI USB Serial Device converter detected
[27278.745281] usb 1-1.3: Detected FT232RL
[27278.746556] usb 1-1.3: FTDI USB Serial Device converter now attached to ttyUSB0
Manual
The manuals Dell lists for download on the S4820T Documentation are actually for an older version of the OS. I found a better manual by searching.
Here’s a link for the Dell Configuration Guide for the S4820T System, version 9.14.1.5.
Configuration Modes
As described in the manual, there are a number of configuration modes, and in the default one you can’t do much.
To enter EXEC mode, simply type enable, and the prompt will change to a #:
Dell>enable
Dell#
To enter CONFIGURATION mode, type conf (or configure), and the prompt will change to (conf)#:
Dell#conf
Dell(conf)#
To go back to a previous configuration mode, type end or exit (I’m not sure of the difference).
Saving Changes
As with much network hardware, configuration changes aren’t saved permanently unless you explicitly write them to persistent storage. To save changes:
Dell#copy running-config startup-config
File with same name already exist.
Proceed to copy the file [confirm yes/no]: yes
!
4475 bytes successfully copied
Aug 1 11:27:06 %STKUNIT0-M:CP %FILEMGR-5-FILESAVED: Copied running-config to startup-config in flash by default
Or more simply:
Dell#write
!
Aug 1 11:27:19 %STKUNIT0-M:CP %FILEMGR-5-FILESAVED: Copied running-config to startup-config in flash by default
The do command
Instead of switching back to EXEC mode for one-off commands, you can prefix the command with do. E.g., to write the configuration to flash from the CONFIGURATION mode, simply type:
Dell(conf)#do write
!
Aug 1 11:30:26 %STKUNIT0-M:CP %FILEMGR-5-FILESAVED: Copied running-config to startup-config in flash by default
Firmware Upgrade
The firmware can be downloaded from Dell Support. You’ll want to save it to a FAT32-formatted USB flash drive.
Insert the USB flash drive into the switch. From CONFIGURATION mode, type dir usbflash: to list the files on the drive:
Dell#dir usbflash:
Directory of usbflash:
1 drwx 16384 Jan 01 1980 00:00:00 +00:00 .
2 drwx 3584 Aug 01 2022 11:17:08 +00:00 ..
5 -rwx 48846608 Jul 29 2022 19:35:48 +00:00 FTOS-SE-9.14.1.12.bin
usbflash: 30736547840 bytes total (30685970432 bytes free)
You can also inspect the image on the drive:
Dell#show os-version usbflash://FTOS-SE-9.14.1.12.bin
<snip>
RELEASE IMAGE INFORMATION :
---------------------------------------------------------------------
Platform Version Size ReleaseTime
S-Series:SE 9.14(1.12) 48846608 May 9 2022 21:06:17
TARGET IMAGE INFORMATION :
---------------------------------------------------------------------
Type Version Target checksum
runtime 9.14(1.12) Control Processor passed
CPLD IMAGE INFORMATION :
---------------------------------------------------------------------
Card CPLD Name Version
stack-unit 0 S4820 SYSTEM CPLD 9
The system comes with two flash locations for a boot image. See what versions are installed currently, and which one is marked to boot:
Dell#show boot system stack-unit 0
Current system image information in the system:
===============================================
Type Boot Type A B
----------------------------------------------------------------------------------------------
stack-unit 0 FLASH BOOT 9.14(1.12) 9.14(1.12)[boot]
When upgrading, I wrote the image to the not-currently-running flash location (not sure if that matters), booted into that, and then upgraded the other spot.
Dell#upgrade system usbflash://FTOS-SE-9.14.1.12.bin A:
...
Update the switch to boot from the other image:
Dell#show boot system stack-unit 0
Current system image information in the system:
===============================================
Type Boot Type A B
----------------------------------------------------------------------------------------------
stack-unit 0 FLASH BOOT 9.14(1.12) 9.14(1.12)[boot]
Dell#conf
Dell(conf)#boot system stack-unit 0 primary system: A:
Dell(conf)#do write
!
Aug 1 11:30:26 %STKUNIT0-M:CP %FILEMGR-5-FILESAVED: Copied running-config to startup-config in flash by default
To restart the switch:
Dell(conf)#do reload
Proceed with reload [confirm yes/no]: yes
Source: YouTube
Factory defaults
My switch arrived with some configuration, so I wanted to reset it to factory defaults before doing any configuration. Note you absolutely must have a serial console when (or after) running this command, or you’ll lose access to the switch. From EXEC mode:
Dell#restore factory-defaults stack unit 0 clear-all
Source: Dell Knowledge Base.
Passwords
The switch has two different types of passwords.
One is the usual user/password to login remotely (not required when using the serial console). You can set that as follows:
Dell(conf)#username admin password <password>
Dell(conf)#Aug 1 14:43:58 %STKUNIT0-M:CP %SEC-5-USER_ACC_CREATION_SUCCESS: User account "admin" created or modified by default from console successfully
The second is an “enable” password, required to enter EXEC mode. It appears to be required before SSH login works.
Dell(conf)#enable password <password>
Don’t forget to save the changes:
Dell(conf)#do write
!
Aug 1 14:45:55 %STKUNIT0-M:CP %FILEMGR-5-FILESAVED: Copied running-config to startup-config in flash by default
Now, a password is required after typing enable:
Dell>enable
Password:
<snip>
Dell#
Conclusion
That wraps up this post on the initial configuration of this Dell S4820T 10GBase-T switch. I plan to follow up with another post or two on the management prot and basic switch configuration.