February 2023 - stunnel-users

stunnel FIPS mode 140-2/ Other Modes
by mehmet ozisik 19 Sep '25

19 Sep '25

Hi All, I would like to ask a question about stunnel fips mode. There are lots of question and answers on the internet related with this, but I could not find any answer related with mine. I am compiling with openssl (auto detecting fips) . Here is a part of confgiure output : checking for FIPS_mode_set... yes configure: FIPS mode detected So I am thinking that fips also is being included. Then I try to run stunnel on target platform (in stunnel.conf fips=yes) and it gives below error : Compiled/running with OpenSSL 0.9.8w-fips 23 Apr 2012 Threading:PTHREAD Sockets:POLL,IPv6 SSL:ENGINE,OCSP,FIPS Reading configuration from file stunnel.conf FIPS_mode_set: 2D06906E: error:2D06906E:FIPS routines:FIPS_CHECK_INCORE_FINGERPRINT:fingerprint does not match there are lots of information about this errror on internet. Then when I configure stunnel.conf with fips=no, stunnel is running successfully. I know that fips=yes means that enables FIPS 140-2 mode and I guess my fips canister does not supoort fips 140-2 mode (I do not know which fips mode it has supported). Now my question is coming : When I set fips=no, stunnel also starts with other available fips modes which the canister included? Or it skips running fips mode completely? Plase inform me if anyone has any idea? Regards

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Requests to cloud server that requires host header
by Lorne Kates 13 Nov '24

13 Nov '24

(related to Akamai message from before-- but I have better troubleshooting information). I'm tying to route traffic through stunnel to a "cloud" based-endpoint. That endpoint has a static server name-- test.authorize.net. (This is the dev sandbox for auth.net) But if you do an nslookup on test.authorize.net, you'll get back a different servername and IP, because it's so wonderfully "cloud". Stunnel apparently tries to connect to the nslookup value. The server rejects the request because it can't route it back to test.authorize.net. I've tried adding "delay = yes" and "sni = test.authorize.net", but neither work. To see this in action, a simple setup with any accept, then connect to test.authorize.net:443 in client = yes mode. This is what a valid response looks like (13 -- give me the darn merchant ID in a POST): https://test.authorize.net/gateway/transact.dll This is what you'll get if you try to use stunnel (400 invalid url) : https://23.195.204.150/gateway/transact.dll So how can I get stunnel to send the proper Request Header (host: test.authorize.net) make sure it's using http/1.1, etc?

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Re: [stunnel-users] CPU 100%
by Eric Eberhard 06 Nov '24

06 Nov '24

Long ago I had a server with a bad network card. Every once in a while it would spew uncontrollable bytes onto the network. If you open a stunnel connection and it does that this could very well be the problem. If it cheap, try changing the network card. If not, you should be able to look in your firewall/router and it will tell you who is sending what bytes to whomever. See if that machine is indeed streaming the bytes in massive quantities. If not, I would suspect your stunnel is getting stuck in it's own loop. There are a million reasons this can happen (well a few less than a million) - such as maybe a bad library in the FreeBSD or a bad choice in the Makefile - such as doing threads or something in a way your O/S does not like (I use threads=fork or whatever it is, instead of actual threading). You might tinker with some of the options that make the stunnel build and try different ones. Especially if stunnel was compiled on a different version of the O/S - could be differences in bytes in things and who knows what. That is all I can suggest beyond setting the debug level to 7 (I think is highest) and then watching the log file. Eric From: stunnel-users [mailto:stunnel-users-bounces@stunnel.org] On Behalf Of Murrey, Brian J. Sent: Wednesday, October 17, 2018 10:57 AM To: stunnel-users(a)stunnel.org Subject: [stunnel-users] CPU 100% We are running stunnel 5.49 on FreeBSD 11.2 and we're running into a problem once in a while. CPU pegs at 100% when we get an stunnel connection from one of our external devices. This affects 100% of all cores and we can't even log in to console. To mitigate this temporarily, we have a script running in the background to watch when stunnel begins to spike and restarts the daemon. It doesn't happen 100% of the time, and so far I have been unable to distinguish what makes the connection do this to the CPU. Have any of you run in to this issue? Sincerely, Brian Murrey System Engineer II, IT Infrastructure _____ NOTICE: This message may contain privileged and confidential information and/or protected health information intended solely for the use of the named recipient and may be privileged or otherwise protected by law. If you are not the intended recipient of this message, you should immediately notify the sender and delete this message. Do not disseminate, reproduce, or review this message or attachments if you are not the intended recipient. The sender or others may have legal rights restricting the dissemination of the information contained in this message and, as a result, remedies against you in the event of the improper dissemination of confidential information, trade secrets, personal information or privileged communications. This message is the work of the sender and does not necessarily reflect the position, views, or policies of TriMedx LLC or its affiliates. WARNING: The integrity and security of this message cannot be guaranteed and may contain or transmit a virus or other illicit code. Neither TriMedx LLC or its affiliates accept liability for any damage attributable to viruses or illicit code transmitted through this message or an attachment.

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older browsers, stunnel and privoxy
by kovacs janos 05 Mar '24

05 Mar '24

sorry to bother, im trying to make older browsers be able to display TLS 1.1 and TLS 1.2 sites. i heard stunnel cant be configured to always forward to the current site address dynamically, thats why i would use privoxy. the browser is configured to send to: 127.0.0.1 443 stunnel config has this at the end: [Tunnel_in] client = yes accept = 127.0.0.1:443 connect = 127.0.0.1:8118 verifyChain = yes CAfile = ca-certs.pem checkHost = localhost 127.0.0.1:8118 is the privoxy address. this is what stunnel writes: LOG5[main]: Configuration successful LOG5[0]: Service [Tunnel_in] accepted connection from 127.0.0.1:3261 LOG5[0]: s_connect: connected 127.0.0.1:8118 LOG5[0]: Service [Tunnel_in] connected remote server from 127.0.0.1:3262 and the browser infinitely loads, and never loads anything or leaves the page. if i remove the last 3 lines, its the same just with this line added: LOG4[main]: Service [Tunnel_in] needs authentication to prevent MITM attacks but it doesnt give an error or anything. with a configuration like: [Tunnel_out] client = no accept = 127.0.0.1:443 connect = 127.0.0.1:8118 cert = stunnel.pem this is what it gives: LOG5[3]: Service [Tunnel_out] accepted connection from 127.0.0.1:3294 LOG3[3]: SSL_accept: 1407609B: error:1407609B:SSL routines:SSL23_GET_CLIENT_HELLO:https proxy request LOG5[3]: Connection reset: 0 byte(s) sent to TLS, 0 byte(s) sent to socket and browser gives a server not found error immediately. im not even sure if i should use client or server configuration in a case like this, but none of them works anyway. all i would need is for my browser to get the pages decrypted, or at least in less than TLS1.1. like how on newipnow.com i can access sites with any encryption, since they are sent to the browser without encryption. the browser just gives an "unencrypted tunnel" warning, which is how i found stunnel, and which is exactly what i need, just locally.

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TPM based mutual tls authentication
by Nyiri, Gabor (Nokia - HU/Budapest) 07 Nov '23

07 Nov '23

Hi, Can you help me how to configure stunnel client to use TPM for mutual TLS authentication? I want to connect with mTLS to a remote server then make this connection available for localhost without mTLS. Thanks for your help in advance! Here is my configuration so far without TPM: debug = debug output = /tmp/stunnel.log foreground = yes [mtls_client] client = yes accept = 127.0.0.1:12019 sni = server-with-mtls.example.com checkHost = server-with-mtls.example.com connect = 1.2.3.4:443 verifyChain = yes CApath = /etc/ssl/certs/ cert = client.crt key = client.key Thanks & br, Gábor Nyíri,

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Can I use SCCM to push the install of stunnel to multiple devices
by kmbpabvmkrmtzuzurk＠bbitf.com 27 Feb '23

27 Feb '23

Just a quick question around this and are there any documentation/guides that could be useful?

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Stunnel Configuration issues
by ringbretson＠keplp.com 22 Feb '23

22 Feb '23

I'm trying to create a FIX application that interfaces with ICE using Stunnel to provide encryption. I'm encountering a handshake failure trying to interface with the FIX application. I've copies portions of the Stunnel configuration file as well as the entire FIX configuration file below. Can you do a quick review of the two configuration files and tell me what I'm doing wrong? Both FIX and Stunnel are running on the same Windows 10 virtual pc. *** Stunnel ERRORS with accept set to 127.0.0.1:83 *** 2023.02.21 20:07:13 LOG5[main]: stunnel 5.68 on x64-pc-mingw32-gnu platform 2023.02.21 20:07:13 LOG5[main]: Compiled/running with OpenSSL 3.0.8 7 Feb 2023 2023.02.21 20:07:13 LOG5[main]: Threading:WIN32 Sockets:SELECT,IPv6 TLS:ENGINE,FIPS,OCSP,PSK,SNI 2023.02.21 20:07:13 LOG5[main]: Reading configuration from file C:\Program Files (x86)\stunnel\config\stunnel.conf 2023.02.21 20:07:13 LOG5[main]: UTF-8 byte order mark detected 2023.02.21 20:07:13 LOG5[main]: FIPS mode disabled 2023.02.21 20:07:13 LOG3[main]: No trusted certificates found 2023.02.21 20:07:13 LOG5[main]: Configuration successful 2023.02.21 20:07:25 LOG5[0]: Service [fix_initiator_session1_tunnel] accepted connection from 127.0.0.1:62314 2023.02.21 20:07:25 LOG5[0]: s_connect: connected 63.247.113.201:443 2023.02.21 20:07:25 LOG5[0]: Service [fix_initiator_session1_tunnel] connected remote server from 192.168.1.219:62315 2023.02.21 20:07:25 LOG3[0]: SSL_connect: ssl/record/rec_layer_s3.c:1605: error:0A000410:SSL routines::sslv3 alert handshake failure 2023.02.21 20:07:25 LOG5[0]: Connection closed/reset: 0 byte(s) sent to TLS, 0 byte(s) sent to socket 2023.02.21 20:07:26 LOG5[1]: Service [fix_initiator_session1_tunnel] accepted connection from 127.0.0.1:62316 2023.02.21 20:07:26 LOG5[1]: s_connect: connected 63.247.113.201:443 2023.02.21 20:07:26 LOG5[1]: Service [fix_initiator_session1_tunnel] connected remote server from 192.168.1.219:62317 2023.02.21 20:07:26 LOG3[1]: SSL_connect: ssl/record/rec_layer_s3.c:1605: error:0A000410:SSL routines::sslv3 alert handshake failure 2023.02.21 20:07:26 LOG5[1]: Connection closed/reset: 0 byte(s) sent to TLS, 0 byte(s) sent to socket *** FIX ERRORS with accept set to 127.0.0.1:49200 *** Same errors in stunnel, but (Socket Error: An existing connection was forcibly closed by the remote host.) in FIX Application *** Stunnel configuration *** [fix_initiator_session1_tunnel] client = yes accept = 127.0.0.1:83 connect = 63.247.113.201:443 cert = stunnel.pem ciphers = PSK PSKsecrets = psk.txt *** FIX 4.4 Configuration *** [DEFAULT] ConnectionType=initiator ReconnectInterval=60 FileStorePath=c:\Temp\WebIce_Initiator FileLogPath=c:\Temp\WebIce_Initiator StartTime=00:00:00 EndTime=23:59:59 SocketConnectHost=127.0.0.1 SocketConnectPort=83 ResetOnLogon=Y ResetOnLogout=Y ResetOnDisconnect=Y [SESSION] BeginString=FIX.4.4 SenderCompID=8655 SenderSubID=0921 TargetCompID=ICE HeartBtInt=30 ValidateFieldsOutOfOrder=N UseDataDictionary=Y DataDictionary=C:\Applications\WebIceInitiator_Pub\FIX44.xml CheckLatency=N SSLEnable=Y SSLProtocols=Tls12 SSLValidateCertificates=N SSLCertificateRevocation=N SSLCertificate=C:\Applications\WebIceInitiator_Pub\Wildcard.ingsoftware.net. pfx SSLCertificatePassword=9322 SSLRequireClientCertificate=N ScreenLogEvents=N ScreenLogShowIncoming=N ScreenLogShowOutgoing=N ScreenLogShowHeartBeats=N

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tstunnel.exe fails to start after updating from 5.67 to 5.68
by Yasuhiro Kimura 21 Feb '23

21 Feb '23

Hello, I install stunnel to my 64bit Windows 10 22H2 PC with official Windows installer and use tstunnel.exe to create TLS connection to IMAP server with configuration file as following ("debug=debug" line is added for debugging purpose). ---------------------------------------------------------------------- client=yes verify=2 checkHost=imap.example.org CApath=C:/Users/yasu/.certs debug=debug [13579] accept=localhost:13579 connect=imap.example.org:143 protocol=imap ---------------------------------------------------------------------- With version 5.67, tstunnel.exe successfully starts as following. ---------------------------------------------------------------------- C:\Users\yasu>tstunnel C:\Users\yasu\Temp\tstunnel.conf 2023.02.19 04:29:11 LOG6[ui]: Initializing inetd mode configuration 2023.02.19 04:29:11 LOG7[ui]: Running on Windows 6.2 2023.02.19 04:29:11 LOG7[ui]: No limit detected for the number of clients 2023.02.19 04:29:11 LOG5[ui]: stunnel 5.67 on x64-pc-mingw32-gnu platform 2023.02.19 04:29:11 LOG5[ui]: Compiled/running with OpenSSL 3.0.7 1 Nov 2022 2023.02.19 04:29:11 LOG5[ui]: Threading:WIN32 Sockets:SELECT,IPv6 TLS:ENGINE,FIPS,OCSP,PSK,SNI 2023.02.19 04:29:11 LOG7[ui]: errno: (*_errno()) 2023.02.19 04:29:11 LOG6[ui]: Initializing inetd mode configuration 2023.02.19 04:29:11 LOG7[ui]: Running on Windows 6.2 2023.02.19 04:29:11 LOG5[ui]: Reading configuration from file C:\Users\yasu\Temp\tstunnel.conf 2023.02.19 04:29:11 LOG5[ui]: UTF-8 byte order mark not detected 2023.02.19 04:29:11 LOG5[ui]: FIPS mode disabled 2023.02.19 04:29:11 LOG6[ui]: Compression disabled 2023.02.19 04:29:11 LOG7[ui]: No PRNG seeding was required 2023.02.19 04:29:11 LOG6[ui]: Initializing service [13579] 2023.02.19 04:29:11 LOG6[ui]: stunnel default security level set: 2 2023.02.19 04:29:11 LOG7[ui]: Ciphers: HIGH:!aNULL:!SSLv2:!DH:!kDHEPSK 2023.02.19 04:29:11 LOG7[ui]: TLSv1.3 ciphersuites: TLS_AES_256_GCM_SHA384:TLS_AES_128_GCM_SHA256:TLS_CHACHA20_POLY1305_SHA256 2023.02.19 04:29:11 LOG7[ui]: TLS options: 0x2100000 (+0x0, -0x0) 2023.02.19 04:29:11 LOG6[ui]: Session resumption enabled 2023.02.19 04:29:11 LOG7[ui]: No certificate or private key specified 2023.02.19 04:29:11 LOG6[ui]: DH initialization skipped: client section 2023.02.19 04:29:11 LOG7[ui]: ECDH initialization 2023.02.19 04:29:11 LOG7[ui]: ECDH initialized with curves X25519:P-256:X448:P-521:P-384 2023.02.19 04:29:11 LOG5[ui]: Configuration successful 2023.02.19 04:29:11 LOG7[ui]: Deallocating deployed section defaults 2023.02.19 04:29:11 LOG7[ui]: Binding service [13579] 2023.02.19 04:29:11 LOG7[ui]: Listening file descriptor created (FD=524) 2023.02.19 04:29:11 LOG7[ui]: Setting accept socket options (FD=524) 2023.02.19 04:29:11 LOG7[ui]: Option SO_EXCLUSIVEADDRUSE set on accept socket 2023.02.19 04:29:11 LOG6[ui]: Service [13579] (FD=524) bound to ::1:13579 2023.02.19 04:29:11 LOG7[ui]: Listening file descriptor created (FD=528) 2023.02.19 04:29:11 LOG7[ui]: Setting accept socket options (FD=528) 2023.02.19 04:29:11 LOG7[ui]: Option SO_EXCLUSIVEADDRUSE set on accept socket 2023.02.19 04:29:11 LOG6[ui]: Service [13579] (FD=528) bound to 127.0.0.1:13579 2023.02.19 04:29:11 LOG7[cron]: Cron thread initialized 2023.02.19 04:29:11 LOG6[cron]: Executing cron jobs 2023.02.19 04:29:11 LOG6[cron]: Cron jobs completed in 0 seconds 2023.02.19 04:29:11 LOG7[cron]: Waiting 86400 seconds ---------------------------------------------------------------------- And if I try `telnet localhost 13579`, then I can successfully connect to IMAP server. But after updating from 5.67 to 5.68, it fails to start as following. ---------------------------------------------------------------------- C:\Users\yasu>tstunnel C:\Users\yasu\Temp\tstunnel.conf [ ] Initializing inetd mode configuration [ ] Running on Windows 6.2 [ ] No limit detected for the number of clients [.] stunnel 5.68 on x64-pc-mingw32-gnu platform [.] Compiled/running with OpenSSL 3.0.8 7 Feb 2023 [.] Threading:WIN32 Sockets:SELECT,IPv6 TLS:ENGINE,FIPS,OCSP,PSK,SNI [ ] errno: (*_errno()) [ ] Initializing inetd mode configuration [ ] Running on Windows 6.2 [.] Reading configuration from file C:\Users\yasu\Temp\tstunnel.conf [.] UTF-8 byte order mark not detected [.] FIPS mode disabled [ ] Compression disabled [ ] No PRNG seeding was required [ ] Initializing service [13579] [ ] stunnel default security level set: 2 [ ] Ciphers: HIGH:!aNULL:!SSLv2:!DH:!kDHEPSK [ ] TLSv1.3 ciphersuites: TLS_AES_256_GCM_SHA384:TLS_AES_128_GCM_SHA256:TLS_CHACHA20_POLY1305_SHA256 [ ] TLS options: 0x2100000 (+0x0, -0x0) [ ] Session resumption enabled [ ] No certificate or private key specified [!] No trusted certificates found [!] Service [13579]: Failed to initialize TLS context [!] Configuration failed [ ] Deallocating temporary section defaults [ ] Deallocating section [13579] ---------------------------------------------------------------------- Why these different results happen? Is it bug of 5.68? Or it there any incompatible change between 5.67 and 5.68? --- Yasuhiro Kimura

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No peer temporary key received
by Michael S. Chusovitin 18 Feb '23

18 Feb '23

Hi folks, is there any chance to grasp why such a line - "No peer temporary key received" - is logged immediately after successful negotiation? It does not look harmful but I cannot understand *how ECDHE can do without the ephemeral key*. 2023.02.17 20:33:41 LOG6[4]: TLS accepted: new session negotiated 2023.02.17 20:33:41 LOG6[4]: TLSv1.2 ciphersuite: ECDHE-RSA-AES256-GCM-SHA384 (256-bit encryption) 2023.02.17 20:33:41 LOG6[4]: No peer temporary key received 2023.02.17 20:33:41 LOG7[4]: Compression: null, expansion: null 2023.02.17 20:33:41 LOG6[4]: s_connect: connecting 127.0.0.1:9000 2023.02.17 20:33:41 LOG7[4]: s_connect: s_poll_wait 127.0.0.1:9000: waiting 10 seconds 2023.02.17 20:33:41 LOG7[4]: FD=524 ifds=--- ofds=r-- 2023.02.17 20:33:41 LOG7[4]: FD=540 ifds=rwx ofds=--- 2023.02.17 20:33:41 LOG5[4]: s_connect: connected 127.0.0.1:9000 The above is logged by Stunnel 5.67/5.68; whereas Stunnel 5.66 logs the very same moments differently: it says "SSL_get_peer_tmp_key: Peer suddenly disconnected" (but this can hardly be true). 2023.02.17 20:27:15 LOG6[4]: TLS accepted: new session negotiated 2023.02.17 20:27:15 LOG6[4]: TLSv1.2 ciphersuite: ECDHE-RSA-AES256-GCM-SHA384 (256-bit encryption) 2023.02.17 20:27:15 LOG3[4]: SSL_get_peer_tmp_key: Peer suddenly disconnected 2023.02.17 20:27:15 LOG7[4]: Compression: null, expansion: null 2023.02.17 20:27:15 LOG6[4]: s_connect: connecting 127.0.0.1:9000 2023.02.17 20:27:15 LOG7[4]: s_connect: s_poll_wait 127.0.0.1:9000: waiting 10 seconds 2023.02.17 20:27:15 LOG7[4]: FD=512 ifds=--- ofds=r-- 2023.02.17 20:27:15 LOG7[4]: FD=528 ifds=rwx ofds=--- 2023.02.17 20:27:15 LOG5[4]: s_connect: connected 127.0.0.1:9000 Thanks in advance, Mikhail

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blat, stunnel, and gmail with an app password
by blat_stunnel2023＠protonmail.com 18 Feb '23

18 Feb '23

I was using a Windows command line blat.exe mailer with stunnel along with a gmail account to send emails from a Windows command line batch file. Gmail started requiring I se the gmail account to allow "less secure" sign in options. That worked for a while, but in May 2022, gmail discontinued that option. It sounds like you can set two factor on the gmail account and then generate an app password for the gmail account. So I did that. I'm stumped on how to get either blat or stunnel to use that gmail app password though. Any ideas? Blat is looking super old though. I see when I set up this computer to with blat-stunnel-gmail, that I ran a line with blat.exe to store the gmail password. I don't see a way to store an app password, but blat is old. This is blat. http://www.blat.net./ Looks like the last update was in 2012, so app passwords may not have even existed then. Is there any way to stunnel to store a gmail app password? My goal is just to send an email from a Windows machine with either a Windows batch file or PowerShell script. It's not mission critical. It's for home use. I just like to get email alerts when my home machines complete some task. If something else works, I'm interested. It needs to work in a batch file though, or at least powershell if a batch file can't work. For my previous set up, I just kept stunnel updated, initially set up blat with the email information, and used only a batch file with blat to send emails from a gmail account. And then it was making sure less secure apps was an option on the gmail account. Now it's been broken for almost a year.

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