On Wed, Mar 07, 2001 at 08:36:58AM -0800, Greg White wrote:
[snip]
> It seems to me that qmail will only try the other MXs if it cannot
> _connect_ to the MX it tries -- an opened but failed connection means
> that it will continue to try the best-preference MX (similar to multiple
> DNS servers in /etc/resolv.conf). Masters of the qmail Source (tm) can
> probably confirm this for us. Not sure if this is covered in the RFCs or
> not, but is seems reasonable behaviour to me -- if this host is
> overloaded, why accept the connection at all? Opening up a new TCP
> connection in an attempt to defer mail seems to me to defeat the purpose
> of deferring it in the first place. ;) tcpserver, at its connection
> limit, does not open a connection at all, neither does inetd.
>
> Try black-holing or firewalling port 25 on the best-preference MX and
> see if I'm right -- I'll bet if you can't reach SMTP on that host at
> all, mail will go to the next MX and all will be well.
This is correct, as far as I know.
Greetz, Peter.
