July 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 04 Mar '24

04 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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Fail to build stunnel 5.70 for windows using xmingw64
by roierachamim＠gmail.com 30 Aug '23

30 Aug '23

Hi, Trying to build stunnel the following warning showed up: network.c: In function 's_read': network.c:737:44: warning: unknown conversion type character 'l' in format [-Wformat=] s_log(LOG_ERR, "s_read: Received %llu out of requested %llu byte(s)", ^ network.c:737:66: warning: unknown conversion type character 'l' in format [-Wformat=] s_log(LOG_ERR, "s_read: Received %llu out of requested %llu byte(s)", ^ network.c:737:24: warning: too many arguments for format [-Wformat-extra-args] s_log(LOG_ERR, "s_read: Received %llu out of requested %llu byte(s)", ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ And one more of the same kind. I wonder how it didn't happen in the official binaries. Are they being built using the instructions in INSTALL.W32 ? Using xmingw-64 ? Roie

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Config stunnel for outgoing mails to Ionos
by a.franken＠management-kommunikation.de 22 Aug '23

22 Aug '23

In these days, our provider Ionos/1&1 starts to accept only encrypted access to its mail server and at least TLS 1.2. There are no problems with incoming mails. In order to be on the safe side with our Win SBS Server 2008 (no comments please!) with outgoing mails, I now have interposed stunnel as recommended many times on the web. This works in principle. Unfortunate exception: In some cases - expecially if the mail recipient has a Microsoft address like @hotmail.de, @live.de, @outlook.com -, sending aborts with error 503 5.5.2 ("Need mail command"). Unfortunately, I'm quite innocent with SMTP, SSL and certificates, but worked hard to create the following stunnel configuration file: socket = l:TCP_NODELAY=0 socket = r:TCP_NODELAY=0 client = yes output = C:\Program Files (x86)\stunnel\stunnel.log [smtpionos] accept = localhost:465 connect = smtp.ionos.de:465 verifyChain = yes verifyPeer = yes CAfile = C:\Program Files (x86)\stunnel\config\amakor2022.pem checkHost = remote.management-kommunikation.de protocolHost = smtp.ionos.de protocolAuthentication = login protocolUsername = OUR_USERNAME protocolPassword = OUR_PASSWORD sslVersionMin = TLSv1.2 sslVersionMax = TLSv1.2 delay = yes protocol = smtp amakor2022.pem is the "PositiveSSL" certificate that we acquired for our subdomain remote.management-kommunikation.de. "Our_Username" and "Our_Password" are of course our correct access data. After spending hours searching the web for a solution, does anyone have a tip what's wrong and what to do?

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can not send
by wizardm＠gmx.de 21 Jul '23

21 Jul '23

hello, I have accounts with gmx, aol and 1&1 (ionos). with gmx and aol I can receive and send. but with 1&1 I can only receive. the stunnel log says "SSL_connect: ssl/record/ssl3_record.c:354: error:0A00010B:SSL routines::wrong version number". in the log of the mail program there is an "error - Unexpected connection termination. Connection lost." what can I do? here is my configuration. [gmx-pop3] client = yes accept = 127.0.0.1:110 connect = pop.gmx.net:995 verifyChain = yes CAfile = ca-certs.pem checkHost = pop.gmx.net OCSPaia = yes [gmx-smtp] client = yes accept = 127.0.0.1:25 connect = mail.gmx.net:465 verifyChain = yes CAfile = ca-certs.pem checkHost = mail.gmx.net OCSPaia = yes [aol-pop3] client = yes accept = 127.0.0.1:10110 ; protocol = pop3 connect = pop.aol.com:995 verifyChain = yes CAfile = ca-certs.pem checkHost = pop.aol.com OCSPaia = yes [aol-smtp] client = yes accept = 127.0.0.1:10025 ; protocol = smtp connect = smtp.aol.com:465 verifyChain = yes CAfile = ca-certs.pem checkHost = smtp.aol.com OCSPaia = yes [1und1-pop3] client = yes accept = 127.0.0.1:1110 connect = pop.ionos.de:995 verifyChain = yes CAfile = ca-certs.pem checkHost = pop.ionos.de OCSPaia = yes [1und1-smtp] client = yes accept = 127.0.0.1:1111 connect = smtp.ionos.de:587 verifyChain = yes CAfile = ca-certs.pem checkHost = smtp.ionos.de OCSPaia = yes thank you very much

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“latest” alias
by David Richard (CajunD) 16 Jul '23

16 Jul '23

Hi Folks, I have found some older discussions about keeping archives and such, but wanted to ask if you could create an alias that always pointed to the latest version. We were hard-linking to a version in /downloads/ and when version 5.69 was removed a few days ago, some automation on our end broke and (as a result of circumstance) caused an outage while we were trying to fix another problem with a remote dependency. We have altered our script to point to the archive version and added checking to ensure any future problems are handled properly. That being said, we will always want the latest version of your software when we build our machine images. And while you do send an announcement, we have to take additional action on our end to get that new version. A “latest” link would allow us to get the latest version automatically when we perform security updates. Thanks for considering this request. David. --- David Richard cajund(a)gmail.com

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securityLevel doesn't work with OpenSSL 3.0
by Yasuhiro Kimura 14 Jul '23

14 Jul '23

Hello, I'd like to use stunnel to acccess SMTP server that has following configuration parameters. Host: smtp.example.org Port number: smtps (465) Encryption method: SMTP over TLS At first I created following configuration file and run stunnel 5.70 with it on FreeBSD 13.2-RELEASE. ---------------------------------------------------------------------- CApath=/home/yasu/.certs client=yes foreground=yes syslog=no verify=2 [12345] accept=localhost:12345 checkHost=smtp.examle.org connect=smtp.examle.org:465 ---------------------------------------------------------------------- But unfortunately stunnel emits following messages and local-side connection.is closed when I connect to 12345 port of localhost. ---------------------------------------------------------------------- 2023.07.14 12:29:12 LOG5[0]: Service [12345] accepted connection from ::1:14632 2023.07.14 12:29:12 LOG5[0]: s_connect: connected 10.0.0.1:465 2023.07.14 12:29:12 LOG5[0]: Service [12345] connected remote server from 192.168.0.1:14633 2023.07.14 12:29:12 LOG5[0]: Certificate accepted at depth=0: C=JP, ST=Tokyo, L=Ohta-Ku, O=EXAMLE.INC, CN=smtp.examle.org 2023.07.14 12:29:12 LOG3[0]: SSL_connect: /usr/src/crypto/openssl/ssl/t1_lib.c:1146: error:1414D172:SSL routines:tls12_check_peer_sigalg:wrong signature type 2023.07.14 12:29:12 LOG5[0]: Connection closed/reset: 0 byte(s) sent to TLS, 0 byte(s) sent to socket ---------------------------------------------------------------------- So I added setting of securityLevel as following. ---------------------------------------------------------------------- CApath=/home/yasu/.certs client=yes foreground=yes securityLevel=1 syslog=no verify=2 [12345] accept=localhost:12345 checkHost=smtp.examle.org connect=smtp.examle.org:465 ---------------------------------------------------------------------- And now I can successfully access to STMP server through stunnel. Next, I also tried it on FreeBSD 14-CURRENT and surprisingly stunnel 5.70 emits following messages even if 'securityLevel=1' is specified in configuration file. ---------------------------------------------------------------------- 2023.07.14 12:31:12 LOG5[0]: Service [12345] accepted connection from ::1:10838 2023.07.14 12:31:12 LOG5[0]: s_connect: connected 10.0.0.1:465 2023.07.14 12:31:12 LOG5[0]: Service [12345] connected remote server from 192.168.0.11:41449 2023.07.14 12:31:12 LOG3[0]: SSL_connect: /usr/src/crypto/openssl/ssl/statem/extensions.c:894: error:0A000152:SSL routines::unsafe legacy renegotiation disabled 2023.07.14 12:31:12 LOG5[0]: Connection closed/reset: 0 byte(s) sent to TLS, 0 byte(s) sent to socket ---------------------------------------------------------------------- So I also tried on 2 other platforms. a. Cygwin's stunnel.exe (version 5.69) b. tstunnel.exe installed by useing stunnel-5.69-win64-installer.exe And result is that the former works fine and the latter emits same message as FreeBSD 14-CURRENT. According to these result it seems the failure is related to the version of OpenSSL. That is, while FreeBSD 13.2-RELEASE and Cygwin use OpenSSL 1.1.1, FreeBSD 14-CURRENT and stunnel-5.69-win64-installer.exe use OpenSSL 3.0. So does this mean securityLevel option doesn't work with OpenSSL 3.0? Regards. --- Yasuhiro Kimura

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