For pop and imap its pretty clear and I have documented on the wiki.
Can someone please state a short example on how nginx smtp proxy works
with
a smtp server.
The documentation on this is very sparse, If you can forward me to the
right
direction, I will write myself the documentation on the wiki.
Withougt authenticatin (MX)
Is it possible to mutiplex to different real smtp servers (If not, its
fine, LVS can do that job)
Is is possible to do something with the header before forwarding the
request to the real smtp sever. (How can real smtp server do RBL checks
if
the IP address is local)
What can nginx do before sending the connection the the smtp server
(Can
it change/add some headers, can in pass the mail through a filter)?
With Authentication
Same questions as above. A short example (even in pseudo code) will be
very
helpful.
What to look out on the real smtp server?
Does the actual IP goes to the real smtp server?
Is it possible to mutiplex to different real smtp servers (If not, its
fine, LVS can do that job)
Nginx send request by http to defined in config server and this server
can return ip of
differend upstreams. So load balancing can be done by this “auth”
server.
Is is possible to do something with the header before forwarding the
request to the real smtp sever. (How can real smtp server do RBL checks
if the IP address is local)
On Sun, Apr 05, 2009 at 01:30:34AM +0400, Anton Y. wrote:
nginx can be used for load balancing between different servers with MTA,
but for load-balancing only better to use something like IPVS (in Linux)
or pf (in BSD).
No, you are somewhat wrong here. As smtp proxy with auth nginx is
really very usefull to move load away from traditional
process-per-connection smtp servers (until user is authenticated).
This saves lots of resources when you have many invalid
connections (e.g. initiated by malware, bruteforce attacks etc.).
This may not be an issue unless you run big mail server
though.
Does anyone have a example config of SMTP without Auth they could post
in this thread? I am just trying to get going a SMTP Relay Proxy to a
internal MTAs from external connections. Or could please point me in the
correct direction.
Cheers
nginx as smtp proxy is useful when using smtp auth. (to dispatch to
different backends)
IMHO nginx as smtp proxy with auth useful only to reuse auth server
created for pop/imap proxy.
For pop3/imap nginx need for proxing different users to different
backend (where mail stored).
In smtp message can be send via random server.
nginx can be used for load balancing between different servers with MTA,
but for load-balancing
only better to use something like IPVS (in Linux) or pf (in BSD).
nginx as smtp proxy is useful when not using smtp auth. (to do ip
based checks)
Without auth (incoming mail) nginx can be used to save resources if only
ip not in RBL proxied
to servers with MTA.
But I don’t know is current nginx version used anywhere in production as
smtp proxy without
auth. IMHO it not ready for production, because of lack smtp pipelining
support. Some MTA
(probably some sendmail versions/configs) have bad habit to use
pipelining even if it support
not adversed in EHLO reply.
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