Commit 92674b
2025-02-28 14:01:28 Samuli Seppänen: Add AvoidRoutingConflicts page| /dev/null .. Pages/AvoidRoutingConflicts.md | |
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| + | **Avoid routing conflicts** |
| + | |
| + | |
| + | The following applies to a routed TUN setup which should just about always be the way to setup OpenVPN. |
| + | |
| + | In order to avoid routing conflicts one should choose subnets carefully for the networks **under ones control**. |
| + | These should be RFC 1918 compliant, https://tools.ietf.org/html/rfc1918. |
| + | |
| + | ``` |
| + | 10.0.0.0 - 10.255.255.255 (10/8 prefix) |
| + | 172.16.0.0 - 172.31.255.255 (172.16/12 prefix) |
| + | 192.168.0.0 - 192.168.255.255 (192.168/16 prefix) |
| + | ``` |
| + | |
| + | Traveling clients like laptops and mobile phones mostly have no control over the network they reside. |
| + | In those cases it becomes even more important to choose **uncommon** subnets. |
| + | |
| + | In the simplest form there are three networks involved, see Figure 1: |
| + | 1. The Server side subnet |
| + | 2. The Tunnel subnet |
| + | 3. The Client side subnet |
| + | |
| + |  |
| + | Figure 1 |
| + | |
| + | There may be no overlap between 1, 2 and 3. |
| + | Basically, normal routing applies which should now be obvious to the network admin. |
| + | |
| + | The following (incomplete) list is comprised of default settings for routers/acces points/switches/etc. |
| + | These are common subnets one should try to avoid: |
| + | |
| + | ``` |
| + | 10.0.0 |
| + | 10.0.1 |
| + | 10.1.1 |
| + | 10.1.10 |
| + | 10.2.0 |
| + | 10.8.0 |
| + | 10.10.1 |
| + | 10.90.90 |
| + | 10.100.1 |
| + | 10.255.255 |
| + | |
| + | 169.254 # APIPA # |
| + | |
| + | 172.16.0 |
| + | 172.16.16 |
| + | 172.16.42 |
| + | 172.16.68 |
| + | |
| + | 172.19.3 |
| + | |
| + | 172.20.10 # IPhone built-in hotspot # |
| + | |
| + | 192.168.0 |
| + | 192.168.1 |
| + | 192.168.2 |
| + | 192.168.3 |
| + | 192.168.4 |
| + | 192.168.5 |
| + | 192.168.6 |
| + | 192.168.7 |
| + | 192.168.8 |
| + | 192.168.9 |
| + | 192.168.10 |
| + | 192.168.11 |
| + | 192.168.13 |
| + | 192.168.15 |
| + | 192.168.16 |
| + | 192.168.18 |
| + | 192.168.20 |
| + | 192.168.29 |
| + | 192.168.30 |
| + | 192.168.31 |
| + | 192.168.33 |
| + | 192.168.39 |
| + | 192.168.40 |
| + | 192.168.42 # Android USB tethering # |
| + | 192.168.43 # Android built-in hotspot # |
| + | 192.168.50 |
| + | 192.168.55 |
| + | 192.168.61 |
| + | 192.168.62 |
| + | 192.168.65 |
| + | 192.168.77 |
| + | 192.168.80 |
| + | 192.168.84 # Google WiFi |
| + | 192.168.85 # Google WiFi |
| + | 192.168.86 # Google WiFi |
| + | 192.168.88 |
| + | 192.168.98 |
| + | 192.168.99 |
| + | 192.168.100 |
| + | 192.168.101 |
| + | 192.168.102 |
| + | 192.168.111 |
| + | 192.168.123 |
| + | 192.168.126 |
| + | 192.168.129 |
| + | 192.168.137 # Windows Phone built-in hotspot # |
| + | 192.168.168 |
| + | 192.168.178 |
| + | 192.168.190 |
| + | 192.168.199 |
| + | 192.168.200 |
| + | 192.168.220 |
| + | 192.168.223 |
| + | 192.168.229 |
| + | 192.168.240 |
| + | 192.168.245 |
| + | 192.168.251 |
| + | 192.168.252 |
| + | 192.168.254 |
| + | |
| + | 200.200.200 |
| + | ``` |
| + | |
| + | |
| + | |
| + | November 5 2019 by Pippin |