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the overview of my situation can be seen here:

overview

I have multiple overlapping networks here, namely 10.0.0.0/8 and 10.64.5.0/24 and 10.64.95.0/24. I've decided to separate them via NAT - using 192.168.88.0 network. The other NAT ("Red") works fine and separates another subnet. R2 and R3 are Mikrotik routers, their respective configs:

R1 is a SOHO TP-LINK MR3220, which is default GW for the machines in pink (10.0.0.0/8 subnet). It serves as an Internet gateway for them. The problem is, I can ping 192.168.88.1 / 2 / 3 (in essence, R2 interface) from "blue" IPs (192.168.40.71), but cannot ping 192.168.40.71 from "pink" machines - the ping is sent to their default GW (10.0.0.1 = TPLink), and the router in turn has static route set - 192.168.40.0 via 10.64.203.88. However, the traceroute to 192.168.88.4 (R3 interface) stops at R2 (10.64.203.88).

I can ping 192.168.88.1 from 192.168.40.71 (blue), but not the other way around. Mikrotik labeled R2 can ping 40.71 however.

All firewalls are disabled.

I suspect I messed something up in the default GW/static routes, but do not know where.

closed as off-topic by Ron Maupin Aug 9 '17 at 23:43

This question appears to be off-topic. The users who voted to close gave this specific reason:

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  • 1
    Is there any reason you need to have overlapping networks? I've seen this happen when companies merge. This won't scale and will be a headache to support. I would give a serious thought to redesigning the network with subnets that do not overlap... You'll be making your life a lot easier. – Mark Jul 18 '16 at 12:08
  • Yes, I know that it's a headache - however, I "inherited" the network setup and now I'm trying to do as much as possible without actually redesigning anything physically. At some point in the future (sooner than later) this is going to happen anyway, but I required a quick and dirty solution :-) – Tryglav666 Jul 18 '16 at 13:04
  • Does R2 have a route to 192.168.40.2/24 via 192.168.88.4? And does R3 have a route to 10.0.0.0/8 (pink) via 192.168.88.1 – Mark Jul 18 '16 at 13:58
  • When companies with overlapping network addresses merge, they often use NAT as a temporary measure until one or both of the networks gets readdressed. It is not your typical inside source NAT. You use outside source NAT for this. Unfortunately, your TP-Link device is off-topic here because the vendor does not offer a paid support option. – Ron Maupin Jul 18 '16 at 14:20
  • Regarding the R2 route - yes it does: i68.tinypic.com/2czwnq1.png – Tryglav666 Jul 18 '16 at 15:04
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R3 does not have a route to 10.0.0.0/8 (pink) via 192.168.88.1.

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