[ALUG] Alternatives to SMTP when the network fails

Brett Parker iDunno at sommitrealweird.co.uk
Wed Dec 8 16:31:05 GMT 2010


On 08 Dec 15:47, Laurie Brown wrote:
> Brett Parker wrote:
> > On 08 Dec 14:47, Mark Rogers wrote:
> 
> [SNIP]
> 
> >> - Setup a VPN between the mail server and the exchange server, and
> >> deliver to the VPN address. This seems like the "best" option
> >> although I have no idea whether it is practical having never tried
> >> it. I'd assume OpenVPN as the best VPN solution? I also don't know
> >> how well it would scale if I want to then do this with lots of other
> >> sites?
> > 
> > That'd be the way that I'd go. They've then got a "static" ip on a
> > private network to you (and yes, I'd set the vpn up to be static for
> > that).
> > 
> > If you've got windows at one end, and linux at the other, using OpenVPN
> > is probably your best bet.
> 
> I'd do the same: OpenVPN is goodness. Note too that Netgear DG834G or
> similar (some Linksys or Draytek models IIRC) support IPSEC VPN
> endpoints, so if you have an IPSEC endpoint-enabled modem/router at each
> end, you're sorted (but OpenVPN doesn't support IPSEC).
> 
> In either case, in the event of an outage you'll have changing IP
> addresses at the remote end, one of which will almost certainly be
> dynamic (3G), so you'll need to use dyndns or similar as well. Also, by
> using dyndns, you could dispense with the VPN, as your server will
> always be able to find the remote address.

It's even better than that, because you're also not likely to have an
external IP at all on 3G, vodafone 3G sticks, in my experience, tend to
throw you in to a nat'd 10.0.0.0/24 address space.

-- 
Brett Parker                     http://www.sommitrealweird.co.uk/
PGP Fingerprint 1A9E C066 EDEE 6746 36CB  BD7F 479E C24F 95C7 1D61



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