I wish I read this thread before changing the port on my DS-2CD2732F-IS camera version 5.2.5. After changing the port through the web interface to 8585, I was not able to access the web interface, though the camera was visible in SADP and pingable at the specified local ip address. There are two options that you can get the camera back to operational state.
Option #1 - Reset the camera. This is an easy option but you do have to get up there and hit the reset button. The firmware itself is unchanged but all setting changes you made are lost and the camera is restored to factory default setting. If you've saved the settings using the Export config file option you can just import the settings. (If you cannot find your exported config file, read this thread,
On Hikvision cameras where does the video/snapshots save to when you download them?)
Option #2 - Reload the firmware to the same version you have. I wouldn't recommend this option but I tried it anyway hoping not have to take apart the camera. You can download the
tftp tool at
https://ipcamtalk.com/threads/hikvision-tftp-update-software.6473/ or
https://www.dropbox.com/s/3hy72q4osstun72/5.30 Downgrader.rar?dl=0 and replace the firmware file digicap.dav with your version. If you follow up the steps outlined in the downloaded file, this process takes a few minutes and you should have a working camera AGAIN. Needless to say that you'd lose all custom settings.
But I did run into one issue while running the tftp tool, which I have used before. Basically the upgrading process failed and the tool kept returning the message, "[date stamp] Resend File Required". I believe the problem was resulted from the way my pc was connected to the local network. Once I connected it directly to the same switch where the camera was connected without going through another router (which was on the same network segment), I was able to run the tftp tool and competed the firmware upgrade process. A big sigh as you can imagine.
I think Hikvision should fix the bug on affected firmware versions. Until then it is not a good idea to change the port. If anyone has a better workaround, I'd be very interested to learn it.