Hi Jonatas, This may have already been answered, but I would like to share my experience with this upgrade of PIX 520 .First of all you have to determine your memory size ( flash, RAM) , you might not see thesize of flash when you do # sh ver but you will see 128MB of RAM and as far I know all PIX box with this RAM has 16MB of flash .Also write down your Serial Number it will help you getting the activation key for VPN-DES or VPN-3DES when you send your request to [EMAIL PROTECTED] and provide show version output to them.If you do # wr t at the end of your config . in ver 4.2(4) you might see your key sometime (it depends). Go to www.cisco.com and download the procedure for upgrading PIX 520 and read the procedure carefully and proced to download the ver. you want (I recommend a lowerver. 5. 12 f.i. first and then another one higher f.i. 5.25), so you will have to download the followings file : bh512.bin, bh525.bin, pix512.bin, pix525. bin , rawrite, readme..The procedure has a small typos when you prepare your floppy disk , after formating youhave to C:\>rawrite and put the file name : bh512.bin instead pix512.bin and follow the procedure. At the end it will ask you for if you want to change the activation key so if you got it from Cisco TAC you can put it know ...and you are done.Caution: If you have another PIX 520 which is your failover PIX when you plug your failover cable you might run in some problems all you have to do is too wait long enough till you PIX's syncronize , to see you can type # show failover and look to see which box is Active and which is in standby. Good luck, Mike ------------------------------------------------------------------------ Get your FREE download of MSN Explorer at http://explorer.msn.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=6934&t=6934 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]