Do I have this right? Network WAN - LAN overlap fix?

[stu593]

Hi. Recently, my Synology RT1900 router notified me that I had a WAN subnet and LAN subnet overlap and I had also been noting that I was losing internet connection in parts of my home network. After several painful hours of trying to figure things out, I am not sure that I have solved the problem. Any help would be very much appreciated, thank you in advance.

Here is my setup:

1. I have my Hitron CODA-4582 set to Bridge mode. 
2. My external IP address is 174.xx (assigned by Rogers, I have no control on this) and the Gateway is 174.xx (IP removed for privacy). 
3. My Synology router's IP address (Local network) is 192.168.1.1, subnet mask 255.255.255.0.
4. The Synology's DHCP server is enabled - with Start IP address 192.168.1.2 and End IP address 192.168.1.128.
5. I have several old routers setup in the house to extend the wifi signal (signal is poor due to the nature of the house’s construction i.e. lots of cement and concrete). Here is the list of the routers, which I have put into bridge or access mode (all of them have DHCP disabled, so that only the Synology is assigning IP addresses).
1. AirPort Extreme (in bridge mode, since this is the only way of disabling the DHCP server) - IP address is 192.168.1.52
2. An Airport Express (connected to the Extreme via network 5E cable) which allows me to stream music from my iPhone to a home theatre system. IP address is 192.168.1.43
3. Also connected to the AirPort Extreme, via network cable, is a D-Link router in the basement. The IP address is 192.68.1.60. Note: I assigned this number (which is within the DHCP range of the Synology server I listed above i.e. the only router with DHCP server enabled) when I logged into the dLink router and changed changed this router to an access point (AP) and also disabled the DHCP server on this router. Will the Synology Router assign a new IP address to it when I power off and then power on the entire network?

I am assuming that the DCHP server is assigning the IP addresses to all 3 routers. Does the setup look OK? Are there any possible conflicts? 

I read somewhere that I should disable any firewalls that might be active on the 3 bridged routers - except the one on the Synology? I have not done this and am wondering if this is necessary?

Lastly, should I assign permanent IP addresses to the routers and to the 2 printers on the network?

Thank you!

Stu

***Added Labels***

[RogersAndy · Accepted solution]

Hey @stu593!

Maintaining a consistent wireless connection with several access points can be a bit of a tricky ordeal for sure but no worries, I'll provide what information I can to help!
LAN subnet and WAN subnet overlap typically implies that the router or access points (LAN) are operating on the same subnet as the modem/gateway (WAN). Based on the IP's provided this doesn't appear to be the case as your WAN and LAN should be on different subnets. Can you confirm for me that the modem's default gateway is still 192.168.0.1?
In addition it's also possible that you may be seeing this error due to an internal network conflict. I'll address that below :).

Regarding any conflicts within the network. Currently your network looks as follows:

[[ Gateway (192.168.0.1) --> Synology (192.168.1.1) ]] --> [[ Airport Extreme (192.168.1.52) --> Airport Express (192.168.1.43) ]] --> DLink (192.68.1.60)

If DHCP is disabled on all but the Synology and the other routers are are acting as pass through access points, then the only concern for conflicts would be static IP's, given you've set the range to 192.168.1.2 - 192.168.1.128. I would recommend setting a range that excludes static IP's within your network if you are to use them (This includes your access points, which I would recommend have static IP's assigned as indicated below. )

[[ Gateway (192.168.0.1) --> Synology (192.168.1.1) ]] --> [[ Airport Extreme (192.168.1.20) --> Airport Express (192.168.1.30) ]] --> DLink (192.168.1.40)
A recommended DHCP range would be 192.168.1.100 - 192.168.1.199 for your client pool as most devices default to xx.2 to xx.99 for reserved addresses. By design DHCP functions under the expectation that nothing other than itself will assign IP's on the network. When it attempts to assign an IP that's already in use, you'll get a conflict and a resulting disconnect from the network. This should help eliminate that as a concern.

Disabling firewalls on each of your access points, as well as UPnP is recommended as each of these functions will be provided by your Synology router. Having additional unnecessary features enabled could impair communication to connected devices. Typically an inability to browse due to a firewall conflict or NAT level issue.

From my experience setting up others, as well as my own home wireless network, these steps have gone a long way to minimizing complications. I hope this helps and definitely let me know if you have any other questions!

@RogersAndy

[stu593]

Dear RogersAndy ... thank you so much, I really appreciate your help. Looks like I am almost there! 🙂

For the modem gateway IP confirmation you asked for:

I can only access the modem-router via 192.168.100.1 (given that the Hitron is in bridge mode). The Private Lan Address I see on the Hitron screen is 192.168.100/24. Based on the Private Lan address , do I need to change your suggested DHCP range? If yes, to what? 

I will assign permanent IP addresses to the routers as you suggest, once I hear back from you 🙂 and I will make sure that firewalls as well as UPnP are turned off for the access points (except for the Synology). 

Thank you for your patience and your help - people like you are such a valuable resource to neophytes like me!

Stu

[Gdkitty]

Though I dont think this would overall effect it..
(at least on the airports, as I dont think there is the choice there)
But I know on some older routers I have used as APs in the past.. when they didnt have a specific AP mode on them.

Was yes to disable the firewall as well as DHCP.  I did do a static address on them (just easier to get at them then).
But one thing I found was to NOT use the WAN port on them.  (only did this on ones which had  a specific AP mode).
Plug the incoming connection to just one of the LAN ports.
Did this on quite a number of Linksys models.

[RogersAndy]

I'm glad to hear it was helpful! 192.168.100.1 is normal so you're good to go there, the main thing is that your WAN and LAN are on different subnets and they are. As such, no need to change the suggested DHCP range :). You should be good to complete the changes and definitely keep us posted if there's improvement or any further issues.

All the best!

@RogersAndy