Connected, but no internet access on Synology router after port forwarding from Uverse

@ezchairwanderer

In reviewing the Synology router user guide it appears to have a firewall. You have specific port requirements. Additionally, it sounds like you will be running your at home network completely off of the Synology router. Therefore, I recommend that you configure the Synology router as a router and place it in DMZ of the 5268ac.

If you have not placed Synology router in DMZ but have made other changes to 5268ac firewall, reset the 5268ac firewall to factory settings (Settings/Diagnostics/Resets page). Configure the Synology router to acept an IP address from the 5268ac DHCP. Find out what address was assigned to the Synology router and go to the Settings/Firewall/Applications, Pinholes and DMZ page to place Synology router into DMZ. If you don't see the Synology router in the list, enter its IP address but in either case be sure to press the Choose pushbutton before proceeding to step 2.

Thank you very much for the response. I will try this out. I think I already tried what you have asked. In fact when I go to the U-Verse router login page and choose the Pineholes and DMZ page, it asks me which device (my laptop, the Synology router or my Android phone) to behave as the DHCP. So I did choose the Synology router. The only thing I did not do is to hit the Choose pushbutton. Also, the IP address Window was empty, but I figured that since it had already given me the Synology router as a choice, I do not have to put in its IP address. Again, I will try this and this time hit the pushbutton as you have recommended.

When you believe you have successfully configured the DMS be sure to go to the Firewall/Status page and confirm.

Even after this, no luck. Here is the set up and what I did.

Setup details

1. Incoming internet signal going to Uverse modem and router in one.
2. Home land line phone connected to phone jack on Uverse - this works fine.
3. Synology router connected to UUverse via CAT 5 cable in slot #1
3. Another VoIP phone (different number) modem connected to Synology router using CAT 5, phone connected to modem - this works fine too.
4. Laptop connected to Synology - Connected by no internet access
5. Several mobile phones connected to Synology Wifi - same issue - connected but no internet access

Attempts to resolve the issue.

1. Turned off Wifi in Uverse by going to the router via wired connection to laptop
2. Turned of SSID broadcast (tried it with SSID broadcast set to on too)
3. Selected Synology router to manage traffic in the Pinhole area you had described.
4. Found out the IP address assigned to the Synology router and plugged that in to the textbox and then hit the Choose pushbutton.
5. In next step, selected third radio button - basically allowing all traffic through to Synology - I believe this is IP passthrough.
6. Power cycled Synology router.
7. Verified Synology router DHCP is turned on - as I believe the router should be able to dish out IP addresses to connected devices.
No luck whatsoever.

My suspicison - with very little knowledge of networking - both routers are somehow giving out IP addresses in the range of 192.168.1.x to xxx. So machines connected to Synology don't know where to send packets to. Some kind of a conflict is happening.

I tried restricting one router to give addresse from 192.168.1.2 to 63 as the other was from 63 to 253. No luck.

I tried to set subnet mask to 255.255.0.0 (one of the other ones in the dropdown, other than default class C mask of 255.255.255.0. Could not save it, as it said there was an error pertaining to the IP addresses.

Someone (actually the ATT technician) suggested I put the Synology router in Access Point mode. When I tried that, the save took for ever and never returned. I lost access to the Synology router when I hit the back button on the browser. I then had to soft reset my Synology router.

Any help appreciated. If I cannot get this resolved, I might pay the one time fee, primarily to understand what exactly they do to fix the problem, or just cancel and stick with TWC.

Thanks!

With the proper configuration of a DMZ on the 5268ac, your Synology should have assumed the same IP address as the 5268ac, obtained from AT&T network. This will cause all data from Synology to go directly to AT&T link to internet, bypassing firewall of 5268ac.

Unless you are using the Synology in bridge mode, you should use an IP network other than 192.168.1.0 downstream from the Synology.

You will have to perform a factory reset on the Synology if it is hung.

AT&T field techs will most likely not be able to help you as they may have this level of training. May I suggest you contact Synology for their recommendations. Another suggestion would be to hire a geek perhaps from Best Buy, being certain they understand both products.

Correct, Synology did get the same IP address as the 5268ac, that is what told me that the IP passthrough has worked.

I have already rasied a ticket with Synology and awaiting their response.

Next I want to try your suggestion of using a network other than 192.168.1.0. Just don't know how to do it. Is it by changing the subnet mask, or simply changing the start and end IP address in the Synology to another non-routable IP range?

If this makes sense, I want to try it before engaging the AT&T third party, called ConnectTech. I guess they might be similar to the Geek Squad from Best Buy.

Thanks again. Its an interesting problem to solve though.

The Synology should be using DHCP and NAT. I would use say a 192.168.2.0 255.255.255.0 . Configure DHCP to use the entire Class-C.

Realize that you not be able to route from any device connected to Synology to any device connected to the 5268ac.

I just set the google DNS address in my router and that did the trick. Since it was saying Connected but no internet made me think that only reason it might not be able to go to any web site meant it was not able to do a look up. I set that in my Synology router and all my devices instantly started working. Including my Synology NAS disk.

Thanks for all the help.