Hi,
My ISP have changed something (I guess) on dhcp server and I can’t find what is this.
“Expires After” is 12 hr, and after that dhcp client stuck in “renewing…” status. If this IP doesn’t renew in “nn” (random) hours someone else may take same IP and connection is not working anymore.
That for, I’ve made small script which is checking “renewing…” status and perform “release”, this keep IP, but also reset contrack, so, this is not working good enough for me.
I’ve tested another router and windows machine and this is renewing without the problem, something is missing to be configured, that for need idea how to log/debug dhcp client and if someone have link to dhcp client packets in details would be great. Also, if someone has same problem any hint would help 
Also, there is possibility that this happen since I’ve upgraded from 5.x to 6.x, I am not sure and can’t test it, don’t have 5.x anymore. I’ve disabled dhcp options, nothing happen, everything works same (dhcp client options are new in 6.x).
BTW.
Someone should change this page, there is no “rebinding…” status but “renewing…”
http://wiki.mikrotik.com/wiki/Manual:IP/DHCP_Client
Thank you in advance,
Dejan