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On 10/5/05, Mathias Sundman <mathias@xxxxxxxxxx> wrote: > On Wed, 5 Oct 2005, Leonard Isham wrote: > > > On 10/5/05, Mathias Sundman <mathias@xxxxxxxxxx> wrote: > >> On Tue, 4 Oct 2005, Leonard Isham wrote: > >>> > >>> Bad connectivity is bad connectivity a VPN will not change that. > >>> > >>> If you application would fail with the connectivity loss it will with > >>> the VPN, or without it... game over... unless you can resolve the > >>> connectivity issue(s). > >> > >> Not entirely true I believe. If "normal" connectivity is lost, some router > >> on the way usually return ICMP destination-unreachble packets causing the > >> TCP connection to be reset instantly. If you run your TCP application over > >> an OpenVPN tunnel packets will just be silently dropped during the network > >> outage until OpenVPN detect the network is down via --ping-restart, so TCP > >> sessions inside the tunnel will survive until they time-out. > >> > > > > Depends on quite a number of "things," including traffic shaping that > > silently drops packets. > > > > What I was attempting to explain is that if the loss of connectivity > > is long enough to interrupt the application a VPN will not fix the > > application. I have seen quite a few applications designed to work on > > a LAN that are pushed into a WAN and or VPN environment and they > > simply do not scale to the expanded environment. > > > > Also frequent connectivity losses can really mess up connections. > > Sure VPNs can make things worse under some circumstances. What I was > trying to say was just that it can also help, as he was asking for under > some circumstances. > > A live example: > > I have a bad wireless (802.11B) network at home that causes my laptop to > loose network connectivity from time to time. All my sessions running > directly over internet then dies, while my SSH session to my email server > that runs over an OpenVPN link survives as my TAP-Win32 adapter never > reports "down". I understand your frame of reference now. My frame of reference is the connectivity loss is not local to either system and would not cause an interface to flap (locally that is). In an internet environment, which I believe the OP is in the likelyhood if local interface flap is usually minimal. -- Leonard Isham, CISSP Ostendo non ostento. ____________________________________________ Openvpn-users mailing list Openvpn-users@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/openvpn-users |