Hi, since several days I try to get stunnel working to add TLS1.2 or higher support to my outdated email client program (Applemail 4.6) as my service provider will stop supporting the old protocols soon.
The protocol of stunnel looks as if the connection gets established well. But as soon I want to send a mail my mail program tries for 10-15s to send an then gives up. In the stunnel protocol (time stamp 16:54:22) the server seems to accept the connection, but about 10-15s later I get: Unexpected socket close (s_read) Connection reset: 0 byte(s) sent to TLS, 0 byte(s) sent to socket
Any ideas what could be the problem? Thanks. conf and protocol attached.
conf: setuid = nobody setgid = nogroup foreground = yes debug = 7 output = /usr/local/etc/stunnel/stunnel.log
[strato-pop3] client = yes verifyChain = yes accept = 127.0.0.1:110 connect = pop3.strato.de:995 CApath = /usr/local/etc/stunnel/ cert = /usr/local/etc/stunnel/stunnel.pem checkHost = pop3.strato.de protocol = pop3
[strato-smtp] client = yes verifyChain = yes accept = 127.0.0.1:25 connect = smtp.strato.de:465 checkHost = smtp.strato.de CApath = /usr/local/etc/stunnel/ cert = /usr/local/etc/stunnel/stunnel.pem protocol = smtp
protocol : 2021.07.22 16:53:49 LOG6[ui]: Initializing inetd mode configuration 2021.07.22 16:53:49 LOG7[ui]: Clients allowed=125 2021.07.22 16:53:49 LOG5[ui]: stunnel 5.59 on x86_64-apple-darwin10.8.0 platform 2021.07.22 16:53:49 LOG5[ui]: Compiled/running with OpenSSL 1.1.1k 25 Mar 2021 2021.07.22 16:53:49 LOG5[ui]: Threading:PTHREAD Sockets:POLL,IPv6 TLS:ENGINE,OCSP,PSK,SNI Auth:LIBWRAP 2021.07.22 16:53:49 LOG7[ui]: errno: (*__error()) 2021.07.22 16:53:49 LOG6[ui]: Initializing inetd mode configuration 2021.07.22 16:53:49 LOG5[ui]: Reading configuration from file /usr/local/etc/stunnel/stunnel.conf 2021.07.22 16:53:49 LOG5[ui]: UTF-8 byte order mark detected 2021.07.22 16:53:49 LOG5[ui]: FIPS mode disabled 2021.07.22 16:53:49 LOG6[ui]: Compression enabled: 0 methods 2021.07.22 16:53:49 LOG7[ui]: No PRNG seeding was required 2021.07.22 16:53:49 LOG6[ui]: Initializing service [strato-pop3] 2021.07.22 16:53:49 LOG6[ui]: stunnel default security level set: 2 2021.07.22 16:53:49 LOG7[ui]: Ciphers: HIGH:!aNULL:!SSLv2:!DH:!kDHEPSK 2021.07.22 16:53:49 LOG7[ui]: TLSv1.3 ciphersuites: TLS_AES_256_GCM_SHA384:TLS_AES_128_GCM_SHA256:TLS_CHACHA20_POLY1305_SHA256 2021.07.22 16:53:49 LOG7[ui]: TLS options: 0x02100004 (+0x00000000, -0x00000000) 2021.07.22 16:53:49 LOG6[ui]: Loading certificate from file: /usr/local/etc/stunnel/stunnel.pem 2021.07.22 16:53:49 LOG6[ui]: Certificate loaded from file: /usr/local/etc/stunnel/stunnel.pem 2021.07.22 16:53:49 LOG6[ui]: Loading private key from file: /usr/local/etc/stunnel/stunnel.pem 2021.07.22 16:53:49 LOG6[ui]: Private key loaded from file: /usr/local/etc/stunnel/stunnel.pem 2021.07.22 16:53:49 LOG7[ui]: Private key check succeeded 2021.07.22 16:53:49 LOG6[ui]: DH initialization skipped: client section 2021.07.22 16:53:49 LOG7[ui]: ECDH initialization 2021.07.22 16:53:49 LOG7[ui]: ECDH initialized with curves X25519:P-256:X448:P-521:P-384 2021.07.22 16:53:49 LOG6[ui]: Initializing service [strato-smtp] 2021.07.22 16:53:50 LOG6[ui]: stunnel default security level set: 2 2021.07.22 16:53:50 LOG7[ui]: Ciphers: HIGH:!aNULL:!SSLv2:!DH:!kDHEPSK 2021.07.22 16:53:50 LOG7[ui]: TLSv1.3 ciphersuites: TLS_AES_256_GCM_SHA384:TLS_AES_128_GCM_SHA256:TLS_CHACHA20_POLY1305_SHA256 2021.07.22 16:53:50 LOG7[ui]: TLS options: 0x02100004 (+0x00000000, -0x00000000) 2021.07.22 16:53:50 LOG6[ui]: Loading certificate from file: /usr/local/etc/stunnel/stunnel.pem 2021.07.22 16:53:50 LOG6[ui]: Certificate loaded from file: /usr/local/etc/stunnel/stunnel.pem 2021.07.22 16:53:50 LOG6[ui]: Loading private key from file: /usr/local/etc/stunnel/stunnel.pem 2021.07.22 16:53:50 LOG6[ui]: Private key loaded from file: /usr/local/etc/stunnel/stunnel.pem 2021.07.22 16:53:50 LOG7[ui]: Private key check succeeded 2021.07.22 16:53:50 LOG6[ui]: DH initialization skipped: client section 2021.07.22 16:53:50 LOG7[ui]: ECDH initialization 2021.07.22 16:53:50 LOG7[ui]: ECDH initialized with curves X25519:P-256:X448:P-521:P-384 2021.07.22 16:53:50 LOG5[ui]: Configuration successful 2021.07.22 16:53:50 LOG7[ui]: Deallocating deployed section defaults 2021.07.22 16:53:50 LOG7[ui]: Binding service [strato-pop3] 2021.07.22 16:53:50 LOG7[ui]: Listening file descriptor created (FD=8) 2021.07.22 16:53:50 LOG7[ui]: Setting accept socket options (FD=8) 2021.07.22 16:53:50 LOG7[ui]: Option SO_REUSEADDR set on accept socket 2021.07.22 16:53:50 LOG6[ui]: Service [strato-pop3] (FD=8) bound to 127.0.0.1:110 2021.07.22 16:53:50 LOG7[ui]: Binding service [strato-smtp] 2021.07.22 16:53:50 LOG7[ui]: Listening file descriptor created (FD=10) 2021.07.22 16:53:50 LOG7[ui]: Setting accept socket options (FD=10) 2021.07.22 16:53:50 LOG7[ui]: Option SO_REUSEADDR set on accept socket 2021.07.22 16:53:50 LOG6[ui]: Service [strato-smtp] (FD=10) bound to 127.0.0.1:25 2021.07.22 16:53:50 LOG7[ui]: No pid file being created 2021.07.22 16:53:50 LOG7[cron]: Cron thread initialized 2021.07.22 16:53:50 LOG6[cron]: Executing cron jobs 2021.07.22 16:53:50 LOG6[cron]: Cron jobs completed in 0 seconds 2021.07.22 16:53:50 LOG7[cron]: Waiting 86400 seconds 2021.07.22 16:54:22 LOG7[ui]: Found 1 ready file descriptor(s) 2021.07.22 16:54:22 LOG7[ui]: FD=4 events=0x1 revents=0x0 2021.07.22 16:54:22 LOG7[ui]: FD=8 events=0x1 revents=0x1 2021.07.22 16:54:22 LOG7[ui]: FD=10 events=0x1 revents=0x0 2021.07.22 16:54:22 LOG7[ui]: Service [strato-pop3] accepted (FD=3) from 127.0.0.1:49864 2021.07.22 16:54:22 LOG7[0]: Service [strato-pop3] started 2021.07.22 16:54:22 LOG7[0]: Setting local socket options (FD=3) 2021.07.22 16:54:22 LOG7[0]: Option TCP_NODELAY set on local socket 2021.07.22 16:54:22 LOG5[0]: Service [strato-pop3] accepted connection from 127.0.0.1:49864 2021.07.22 16:54:22 LOG6[0]: s_connect: connecting 81.169.145.131:995 2021.07.22 16:54:22 LOG7[0]: s_connect: s_poll_wait 81.169.145.131:995: waiting 10 seconds 2021.07.22 16:54:22 LOG7[0]: FD=6 events=0x1 revents=0x0 2021.07.22 16:54:22 LOG7[0]: FD=13 events=0x5 revents=0x0 2021.07.22 16:54:22 LOG5[0]: s_connect: connected 81.169.145.131:995 2021.07.22 16:54:22 LOG5[0]: Service [strato-pop3] connected remote server from 192.168.17.130:49865 2021.07.22 16:54:22 LOG7[0]: Setting remote socket options (FD=13) 2021.07.22 16:54:22 LOG7[0]: Option TCP_NODELAY set on remote socket 2021.07.22 16:54:22 LOG7[0]: Remote descriptor (FD=13) initialized 2021.07.22 16:55:22 LOG3[0]: Unexpected socket close (s_read) 2021.07.22 16:55:22 LOG5[0]: Connection reset: 0 byte(s) sent to TLS, 0 byte(s) sent to socket 2021.07.22 16:55:22 LOG7[0]: Remote descriptor (FD=13) closed 2021.07.22 16:55:22 LOG7[0]: Local descriptor (FD=3) closed 2021.07.22 16:55:22 LOG7[0]: Service [strato-pop3] finished (0 left) 2021.07.22 16:55:22 LOG7[0]: str_stats: 1 block(s), 32 data byte(s), 90 control byte(s) 2021.07.22 16:55:22 LOG7[0]: str_stats: 32 byte(s) at network.c:735
I get exactly the same problem with Mac OS 10.9 and Thunderbird as email client. The above post was with OS 10.6 and Appelmail. So the problem seems to be on the stunnel (config?) side.
On Thu, 22 Jul 2021 15:35:56 -0000 [email protected] wrote:
But as soon I want to send a mail my mail program tries for 10-15s to send an then gives up.
[...]
protocol = smtp
[...]
I get exactly the same problem with Mac OS 10.9 and Thunderbird as email client. The above post was with OS 10.6 and Appelmail. So the problem seems to be on the stunnel (config?) side.
Hi,
"protocol = smtp" on client service implies STARTTLS command and, so, implies response from server accordingly to start the TLS session.
Are you sure that strato.de servers offers plain text and TLS upon requests via STARTTLS?
Otherwise, remove the protocol line or comment out with a semicolon (;)
https://datatracker.ietf.org/doc/html/rfc2487
Regards.
Javier wrote:
Hi,
"protocol = smtp" on client service implies STARTTLS command and, so, implies response from server accordingly to start the TLS session.
Are you sure that strato.de servers offers plain text and TLS upon requests via STARTTLS?
Otherwise, remove the protocol line or comment out with a semicolon (;)
https://datatracker.ietf.org/doc/html/rfc2487
Regards.
Thanks!! that did it.
I had also to comment out protocol = pop3 to get POP working.
Moreover I commented out verifyChain = yes checkHost = ... as stunnel complained about the server certivicate. I still hope I will be able fix that somehow, but the essential is that mail is up again on that account.
-
Javier -
zfefm＠gmx.de