[Openvpn-devel] openvpn-2.0_beta1: tunnel MTU a bit too large

2004-05-16 Thread Denis Vlasenko
# dd if=/dev/zero count=1 bs=7000 | nc -nuvvv -w1 1.1.5.5 284 over tunnel: 11:09:20.930621 > 0800 1468: IP (tos 0x0, ttl 64, id 46021, offset 0, flags [+], length: 1452) 1.1.5.6.1025 > 1.1.5.5.284: [bad udp cksum c815!] UDP, length: 7000 11:09:20.930657 > 0800 1468: IP (tos 0x0, ttl 64, id 460

Re: [Openvpn-devel] openvpn-2.0_beta1: tunnel MTU a bit too large

2004-05-16 Thread Denis Vlasenko
> Or maybe I'm mistaken and I shall set --link-mtu not to the value > reported by 'ip a l dev eth0' (i.e. max IP packet size), but > to the max *UDP* packet size? 1500-28=1472, then. Not every user > knows IP overhead size. I don't. I looked at tcpdump to figure out. "Double frag" bug does not hap

Re: [Openvpn-devel] Openvpn clustering

2004-05-16 Thread James Yonan
Beta2 has a new feature where you can run the OpenVPN server on multiple machines, and then give clients a DNS name which maps to multiple IP addresses. The client will choose one of the IPs randomly. If there's a ping-restart event, the client will restart and use a different IP from the list.

Re: [Openvpn-devel] openvpn-2.0_beta1: tunnel MTU a bit too large

2004-05-16 Thread James Yonan
Denis, There are two ways of setting the MTU in OpenVPN, one is to use --tun-mtu which doesn't include any encapsulation overhead, the other is to use --link-mtu which sets the maximum encrypted UDP datagram size sent between OpenVPN daemons after encapsulation. 2.0 takes a different approach to