Jay Lee wrote:
Martijn Lievaart said:
[ off-list, my phone does not seem to understand mailinglists ]
>Yes I understand. The reason I ask is that for IPv4, I am forced to >use a external relay server with my ISP. However, for IPv6 it is not >required. In fact, my ISPs relayserver does not support IPv6 at all.
You could try to use your firewall to dnat all ipv4 connections to your providers mailserver. It's a dirty trick, but I think it will work.
F.I. Using iptables on linux (from memory, may contain mistakes):
iptables -A POSTROUTING -t nat -s <your-mailserver-ipv4> -p tcp --dport 25
-j DNAT --to <isp-smarthost>
I had tried something like this, the problem comes when your users try to
do authenticated smtp with another mail server which would obviously fail
to login to your ISP's smtp server.
"Forced to use an external relay server" and "authenticated smtp with another mail server" seem mutually exclusive to me anyhow.
There are other tricks though. I assume your users are local on the mail server, otherwise the "-s" above takes care of the problem already and it should just work.
1) If on linux, use the owner match of iptables to only redirect connections of the courier user. Obviously, you need to do this on the machine running courier itself. Caveats: I don't know if the owner match works in POSTROUTING. In that case you'll need to mark the connections and redirect on the mark. I think you need to get the owner match from patchomatic, which means patching your kernel.
2) Move the courier to another machine, that does not need to send mail other than through the relay. In that situation the firewall trick works again.
HTH, M4
------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ courier-users mailing list [email protected] Unsubscribe: https://lists.sourceforge.net/lists/listinfo/courier-users
