OpenVPN on CentOS VS DD-WRT or OpenWRT: Difference between revisions

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Environment(s): CentOS 7 and DD-WRT (late 2019 version on a Buffalo Tech WZR-600DHP Router) with OpenVPN version 2.4.7 on ALL devices.

=== The Problem ===

Well, there were multiple issues, but for the sake of focus let's deal with the routing issue.

=== Notes and the Solution ===

There are several websites that give examples for the ifconfig-push command in a "CCD" configuration file for clients that are similar to this: ifconfig-push WhatEverIPAddress1 WhatEverIPAddress2, example: ifconfig-push 192.168.100.11 192.168.100.1. This is not correct. The documentation notes: ifconfig-push WhatEverIPAddress "Subnet Mask of target subnet on server". A correct example: ifconfig-push 192.168.100.11 255.255.255.0.

One difference between the CentOS implementation / compilation and DD-WRT or OpenWRT is that a CentOS OpenVPN server defaults to a "subnet" type for the "topology" command. DD-WRT and OpenWRT default to "Point to Point". This can cause routing issues

The "client" command cannot be used in a "CCD" configuration file

Several websites make comments about various ways to have a client automatically reconnect with a server. Most of it is crap. Tested this and it works (on server): keepalive 5 15 This command is sent as part of the client configuration and means ping server every 5 seconds and if you don't receive a reply for 15 seconds, then reconnect. Works great.

@@ Line 1: / Line 1: @@
 Environment(s): CentOS 7 and DD-WRT (late 2019 version on a Buffalo Tech WZR-600DHP Router) with OpenVPN version 2.4.7 on ALL devices.
+=== The Problem ===
+Well, there were multiple issues, but for the sake of focus let's deal with the routing issue.
+=== Notes and the Solution ===
+There are several websites that give examples for the ifconfig-push command in a "CCD" configuration file for clients that are similar to this: ifconfig-push WhatEverIPAddress1 WhatEverIPAddress2, example: ifconfig-push 192.168.100.11 192.168.100.1.  This is not correct.  The documentation notes: ifconfig-push WhatEverIPAddress "Subnet Mask of target subnet on server".  A correct example: ifconfig-push 192.168.100.11 255.255.255.0.
+One difference between the CentOS implementation / compilation and DD-WRT or OpenWRT is that a CentOS OpenVPN server defaults to a "subnet" type for the "topology" command.  DD-WRT and OpenWRT default to "Point to Point".  This can cause routing issues
+The "client" command cannot be used in a "CCD" configuration file
+Several websites make comments about various ways to have a client automatically reconnect with a server.  Most of it is crap.  Tested this and it works (on server): keepalive 5 15  This command is sent as part of the client configuration and means ping server every 5 seconds and if you don't receive a reply for 15 seconds, then reconnect.  Works great.