password recovery of the Cisco SG200-SG500

Reboot the switch. You will see a prompt during boot right after the cisco logo made out of #s that says

"Autoboot in 2 seconds - press RETURN or Esc. to abort and enter prom." 

 

Hit return, and you will get the following startup menu:

 

    Startup Menu

 

SG200-26 password reset  Download Software

SG200-26 password reset  Erase Flash File

SG200-26 password reset  Password Recovery Procedure

SG200-26 password reset  Set Terminal Baud-Rate

SG200-26 password reset  Stack menu

SG200-26 password reset  Back

Enter your choice or press 'ESC' to exit:

 

You'll want  SG200-26 password reset  Password Recovery Procedure  and follow the prompts to reset the password without erasing your config file.

DHCP for Multiple vlans

most of time, we use one DHCP server assigning ip for multiple vlans, then configure ip helper address on the SVI to forward the DHCP request to DHCP server. when you are using Windows 2008 server, you might have problem with "superscope" setting, put multiple subnet within one superscope, the client ( especially the  cisco IP phone). in this case, you need convert the superscope to multiple regular scope.

second point is CDP, when you use multiple brand IP phones, the voice vlan can't detected by CDP, you might need enable LLDP.