As the thread's title suggests, this is for those of you who'd like to stick their Cisco EPC3925 modem/router devices from UPC into true Bridge mode without DMZ'ing and double NAT'ing. I have been unsatisfied with the not being able to enable it since day one. This is the solution for everyone who would prefer not to use the EPC3925's thin and terrible routing functions by using another router of your own choosing to handle all of that for you while not having to DMZ or double NAT to get it to work.
The questions that are probably on your mind is how can it be done and is it safe? The answer to both is simply: yes, 100%. I'm posting this right now from my EPC3925 bridged with my WNDR3700v1! The best and re-assuring part is: doing this won't break your phone service like it did with the EPC2425. Myself and some other users have tested the phone service while in Bridge mode, both making and receiving calls, and it was 100% successful without any issues or delays in connecting the calls. However, if you want to go back to Router mode for whatever reason, you can do so at any time just as easily as you enabled Bridge mode (see the IMPORTANT NOTE at the bottom of this post).
The fact is, I had a feeling that UPC might have been lazy about removing the functionality and it's true, they half-assed it. They simply hid the functionality by removing some client-side code from the Management page, but the ASP server-side code is still intact. I haven't seen the server-side code as I haven't hacked the device to dump the firmware. I had a suspicion and I went about trying to prove it. It could just as easily gone the other way as far as I was concerned at the time. The solution then is simple; replace the client-side HTML code that was removed! Don't worry, I'll explain how to do it properly. Please keep reading...
So, just for reference only, this is similar to the code that was removed by UPC:
!!! REMEMBER !!!
Please be reminded that after setting the EPC3925 into Bridge mode, UPC's phone service will continue to work as it always has. This has been tried and tested and the problems facing the EPC2425 in Bridge mode were not carried over to the EPC3925. I'm reiterating this here for anyone who may have skimmed over the first few paragraphs of this post.
- A web browser or browser extension that is capable of live manipulation of a website's HTML source code (Opera is my browser of choice for this task)
1. Connect to the EPC3925's web configuration using Ethernet and disable all routing functions (DHCP, Wireless, Firewall, DMZ, UPnP, and any active port forwards) just to be safe. Wireless at the very least, won't get disabled automatically when the device is put into Bridge mode.
2. Navigate to the Administration > Management page and view the page's source code.
3. Copy the new HTML code in full, which I have provided at: http://pastebin.com/W0eQy7mM.
4. Select all the HTML code in the EPC3925's Management page source and paste in the new HTML code to replace it (don't worry, it's not a permanent change - it will revert back once you refresh - this won't void your warranty!).
5. Apply the changes and switch back to the EPC3925's Management page's tab, where you should now see a new menu called "Working Mode" at the top.
6. Select "Bridged Only" and then Apply.
7. Your EPC3925 should then reboot automatically to effect the changes. When it comes back up, it'll be in Bridge mode. You can now navigate to the web configuration using http://192.168.100.1.
8. Set your own cable router to bridge with the EPC3925 and you should then be online. You're on your own on this one as every router is different!
That's it! Again, if you're having trouble, I suggest you use Opera to do this as it's perfect for the job and it's really easy. If you're still having trouble, hit me with a PM with as much details as possible about the problem(s) you're having and with what you have tried (if anything) to remedy them, and I'd be happy to help.
Just to explain a bit further: the concept behind the HTML code is that it adds more POST data to the form on the Management page, POST data that was there before UPC took it away, which the ASP server-side code still checks for; that is why it is possible to enable Bridge mode without resorting to hacking the device to install custom firmware and therefore risk bricking it. We're not adding the functionality back, we're just bringing it out of hiding. This is 100% safe and I would recommend it to anyone who wants to use their own cable router.
If you want to revert back to Router mode for whatever reason, you can do this using one of two methods.
Method 1: Repeat the steps above from scratch and switch back to "Router Mode" via the "Working Mode" menu (this will put you right back where you started with your previous custom settings intact).
Method 2: Perform a hard reset by sticking a pin into that "Reset" hole at the back of the device (you'll lose all your previous custom settings by using this method).
Here's a few images showing the "Working Mode" menu back with a bang! You'll also see my WNDR3700v1 getting the public IP dynamically from the ISP, whereas using a static LAN IP was necessary when DMZ'ing and double NAT'ing, to ensure a direct path to the Internet through the EPC3925's DMZ. The last image shows the Voice page when in Bridge mode with everything looking normal and operational for phone users.