I have the ipcam DS-2CD2632f that for some days is no longer detected in the network. I noticed from the LEDs that turn off and on again at equal intervals of time. I tried to reset, but I realized that I can not even reset it.
I have a vague recollection that there is a reset button under the small hatch under the sun cover.
If so - power off, press the button, power on and keep the button pressed for at least 20 seconds.
Have you allowed access in to the camera from the internet? eg 'port forwarding' or UPnP enabled on both the router and camera.
If so - it may have been hacked.
The Hikvision tftp updater can be used for firmware recovery or installation.
The program and instructions (but not the firmware) can be downloaded from the second Dropbox link on this post : Custom Firmware Downgrader 5.3.0 Chinese to 5.2.5 English