A debian bug report was submitted that inspired me to look deeper into the operation of --dev and the new --dev-name flag.
--dev-name was a patch for tun.c which I received a few months ago, which only really does anything for linux 2.4. On first glance it appeared nominally useful, so I merged it, but on further inspection it appears to be mostly redundant with --dev. It appears that the motivation for implementing --dev-name was that --dev assumes its argument is either "tun", "tap", "null", or tun/tap with a unit number (e.g. "tun4"). But --dev is limited in that it doesn't allow arbitrary renaming. In OpenVPN 1.3.2, if the --dev argument was larger than 3 chars, it was assumed that a unit number was present. In 1.4.1 that test was changed so that an ascii digit needed to be present to assume a unit number. If a unit number was present, then the name of the device (as it appears in ifconfig) would be changed to reflect the explicit unit number. What I think probably inspired the debian bug report is that in 1.3.2 if you said "--dev foobar --dev-type tun", openvpn would have renamed the tun device to foobar, because foobar is > 3 characters. In 1.4.1, no rename would occur because "foobar" doesn't contain any numerical digits. In 1.4.1, you would need to say "--dev tun --dev-name foobar" to get the same effect. This seems somewhat arbitrary and confusing. My conclusion is that the implementation of --dev and --dev-name is mostly redundant because --dev can just as easily set the device name based on its argument, if that argument is something other than "tun", "tap", "null". The current operation of "--dev tun" or "--dev tap" would be preserved so that a dynamic unit number would be allocated if, for example, "--dev tun4" is given. But you could also specify "--dev foo --dev-type tun" and a tun device named foo would be created. I've patched the current development release to remove --dev-name, and to allow --dev to set a specific device name as in the above paragraph. Download: http://openvpn.sourceforge.net/beta/openvpn-1.4.1.4.tar.gz (or CVS) James
