I have one connection that works, and another which fails; but they have
equivalent settings. Please help me resolve this.
A fragment of the config for the connection that works:
[Lopham-smtp]
client = yes
accept = 127.0.0.1:52025
connect = mail.lopham.co.uk:465
The server mail.lopham.co.uk is hosted by a service that I pay for.
A fragment of the config for the connection that fails:
[zen-smtp]
client = yes
accept = 127.0.0.1:26025
connect = mailhost.zen.co.uk:587
The failure in the log is 2026.06.02 12:22:48 LOG3[1]: SSL_connect:
Connection reset by peer (WSAECONNRESET) (10054).
The server mailhost.zen.co.uk is hosted by my internet connection provider
(Zen Internet). When I make the connection without using stunnel the
connection works OK. My SMTP settings in Outlook 2010 are:
Server = mailhost.zen.co.uk
Authentication = Yes
Port = 576
Encryption = TLS
So I set debug = 7
The log shows:
2026.06.02 12:22:48 LOG7[1]: Service [zen-smtp] started
2026.06.02 12:22:48 LOG7[1]: Setting local socket options (FD=504)
2026.06.02 12:22:48 LOG7[1]: Option TCP_NODELAY set on local socket
2026.06.02 12:22:48 LOG5[1]: Service [zen-smtp] accepted connection from
127.0.0.1:53292
2026.06.02 12:22:48 LOG6[1]: failover: priority, starting at entry #0
2026.06.02 12:22:48 LOG6[1]: s_connect: connecting 212.23.1.19:587
2026.06.02 12:22:48 LOG7[1]: s_connect: s_poll_wait 212.23.1.19:587: waiting
10 seconds
2026.06.02 12:22:48 LOG7[1]: FD=468 ifds=rw ofds=--
2026.06.02 12:22:48 LOG5[1]: s_connect: connected 212.23.1.19:587
2026.06.02 12:22:48 LOG5[1]: Service [zen-smtp] connected remote server from
127.0.0.1:53293
2026.06.02 12:22:48 LOG7[1]: Setting remote socket options (FD=468)
2026.06.02 12:22:48 LOG7[1]: Option TCP_NODELAY set on remote socket
2026.06.02 12:22:48 LOG7[1]: Remote descriptor (FD=468) initialized
2026.06.02 12:22:48 LOG6[1]: SNI: sending servername: mailhost.zen.co.uk
2026.06.02 12:22:48 LOG7[1]: No previous session to resume
2026.06.02 12:22:48 LOG6[1]: Peer certificate required
2026.06.02 12:22:48 LOG7[1]: TLS state (connect): before SSL initialization
2026.06.02 12:22:48 LOG7[1]: TLS state (connect): SSLv3/TLS write client
hello
2026.06.02 12:22:48 LOG3[1]: SSL_connect: Connection reset by peer
(WSAECONNRESET) (10054)
2026.06.02 12:22:48 LOG5[1]: Connection reset: 0 byte(s) sent to TLS, 0
byte(s) sent to socket
2026.06.02 12:22:48 LOG7[1]: remote_fd reset (FD=468)
2026.06.02 12:22:48 LOG7[1]: Remote descriptor (FD=468) closed
2026.06.02 12:22:48 LOG7[1]: local_rfd/local_wfd reset (FD=504)
2026.06.02 12:22:48 LOG7[1]: Local descriptor (FD=504) closed
2026.06.02 12:22:48 LOG7[1]: Service [zen-smtp] finished (0 left)
The log does not show me why the connection is reset by the peer.
Can anybody help, please?
Regards,
== Graham
