proxy dual server setup clarification

Marc Roos M.Roos at
Mon Nov 25 12:39:19 EET 2019

Hi Sami,

I have this proxy on pop3/imap working however, I can't get this lmtp to 

In theory only these configuration changes, should allow messages to be 
directed for account: test to server svr1 not?

lmtp_proxy = yes

protocol lmtp {
  # Space separated list of plugins to load (default is global 
  passdb {
  driver = passwd-file
  args = /etc/dovecot/special-passdb
  default_fields = proxy=y host=svr1

bash-5.0# cat /etc/dovecot/special-passdb

bash-5.0# cat /tmp/test.msg | /usr/libexec/dovecot/lmtp
Info: Connect from local
220 081b883fa2bc Dovecot ready.
250 2.1.0 OK
Panic: file connection.c: line 380 (connection_update_properties): 
assertion failed: (conn->remote_port != 0)
Aborted (core dumped)

-----Original Message-----
Subject: Re: proxy dual server setup clarification

> On 12 Nov 2019, at 16.03, Marc Roos via dovecot <dovecot at> 
> I want to migrate mail users to a new environment. 
> If I setup a new server next to the old server, and enable proxy on 
> both. Is this then enough to migrate user by user with the passdb 
> host=newsvr option to the new environment?
> Eg. I do not need to configure a director setup? 
> I only need to enable proxy for imap and lmtp on both servers? 
> (messages on the oldsvr will be proxied to the newsvr?)

You need just one proxy where the user session is authenticated and then 
 forwarded to either backend depending on the host value. You don't need 
to "enable proxy" on any backend or use director.


More information about the dovecot mailing list