now i have problem on DHCP on ASA 5505, on ASA 5505 i was configure DHCP server provide to my client but i would like to fix ip addres( i mean that i dont want to renew ip add, and want to fix ip forever) but i don't know which command that i can do this?
I have done this before on a Cisco L3 Switch such as 6509, 3750 etc. but never on a Cisco Firewall. I don't believe this feature is supported on Cisco Firewall (even on the latest image version 8.4). However, if you do have Cisco ACS in place, then we can make this requirement happen, with the help of Cisco dot1x. This feature will constantly assign the same user is with the same IP Address (c/w with the same policies), anywhere the user plugs in his/her laptop in the LAN.
Please refer to this URL as well https://supportforums.cisco.com/thread/2037237
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You can increase the lease time to the maximum supported on the ASA (1,048,575 seconds), which is about 12 days.
However you can't configure it to have fix ip address forever. If you require fix ip, you should just configure it manually on the client.
Here is all the supported commands for DHCP on the ASA: