August 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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Stunnel hangs with static build with openssl 1.1.1c
by eklein＠triple-eye.nl 07 Sep '23

07 Sep '23

I successfully cross compiled and built a static version of stunnel for ARM. It works with stunnel 5.70 and openssl 1.1.1b If however, I try to use openssl 1.1.1c, stunnel hangs. I narrowed the problem down to the following call in compression_init in ssl.c: comp_methods[COMP_NONE]=sk_SSL_COMP_new_null(); The program does not get past this point. I also tried to build with openssl 1.1.1v and 3.0.0, to no avail. I am using the following commands: To build openssl: ./Configure linux-armv4 --prefix=/home/erik/Documents/openssl-1.1.1b/install --openssldir=/home/erik/Documents/openssl-1.1.1b/install threads shared make CC=arm-linux-gnueabi-gcc make install To build stunnel: sed -i 's/^stunnel_LDFLAGS = /&-all-static /' src/Makefile.in export CFLAGS='-Os -fomit-frame-pointer -pipe' ./configure --with-ssl=/home/erik/Documents/openssl-1.1.1b/install --disable-fips --disable-shared --enable-static --disable-silent-rules --build x86_64-pc-linux-gnu --host arm-linux-gnueabi make What is the difference between openssl1.1.1b and 1.1.1c which causes this problem?

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error:0A000126 on windows 10
by Stewart Anderson 02 Sep '23

02 Sep '23

Hi, First apologies I posted this question on a google stunnel group, but I realise that does not have much activity, so posting here also. I am trying to get stunnel up and running and getting the error in the subject. The full error text is: "SSL_accept: ssl/record/ssl3_record.c:354: error:0A00010B:SSL routines::wrong version number" I have a simple service which seems to load fine. I have stunnel up at the "server side" on a VM in azure and if I telnet to the VM public address I can see the activity in the stunnel logs on the VM, so I know at least a pipe is open. I can hit the port server side and see the log activity in stunnel also. If I try a telnet to the local stunnel accept port. I see the error above. This is the full log. 2023.08.23 11:01:04 LOG7[service]: Found 1 ready file descriptor(s) 2023.08.23 11:01:04 LOG7[service]: FD=604 ifds=r-x ofds=--- 2023.08.23 11:01:04 LOG7[service]: FD=664 ifds=r-x ofds=r-- 2023.08.23 11:01:04 LOG7[service]: Service [dev-dev-testHarness] accepted (FD=708) from 127.0.0.1:10756 2023.08.23 11:01:04 LOG7[service]: Creating a new thread 2023.08.23 11:01:04 LOG7[service]: New thread created 2023.08.23 11:01:04 LOG7[4]: Service [dev-dev-testHarness] started 2023.08.23 11:01:04 LOG7[4]: Setting local socket options (FD=708) 2023.08.23 11:01:04 LOG7[4]: Option TCP_NODELAY set on local socket 2023.08.23 11:01:04 LOG5[4]: Service [dev-dev-testHarness] accepted connection from 127.0.0.1:10756 2023.08.23 11:01:04 LOG6[4]: Peer certificate not required 2023.08.23 11:01:04 LOG7[4]: TLS state (accept): before SSL initialization 2023.08.23 11:01:04 LOG7[4]: TLS alert (write): fatal: decode error 2023.08.23 11:01:04 LOG3[4]: SSL_accept: ssl/record/rec_layer_s3.c:303: error:0A000126:SSL routines::unexpected eof while reading 2023.08.23 11:01:04 LOG5[4]: Connection reset/closed: 0 byte(s) sent to TLS, 0 byte(s) sent to socket 2023.08.23 11:01:04 LOG7[4]: Local descriptor (FD=708) closed 2023.08.23 11:01:04 LOG7[4]: Service [dev-dev-testHarness] finished (0 left) What am I missing, I haven't used stunnel for quite a while and previous effort were on linux and I did not see this problem then. Using telnet/TNC as the local test tools and stunnel was installed with bare default installation. The only thing I have done different is to set a config fragment folder to separate services on the sever side and they report as loading fine. any help greatly appreciated. Stu

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Need help setting up new stunnel config
by Mark Foley 31 Aug '23

31 Aug '23

I used stunnel about 5 years ago and now I want to use it again, but my notes are terrible and I'm having trouble getting started. I want to create a connection between Windows computer on port 3389. The "client" will be some remote Windows computer, perhaps at someone's home office. The "server" will be a Windows workstation at the office. I've installed stunnel 5.70 on a Windows 10 workstation at the office, hostname COMMONW10. I'm at a loss creating the config file on this machine. I have: [COMMONW10] ;client = yes accept = 3389 ;connect = ???:xxxx CAfile = stunnel.pem The stunnel.pem was create when I installed stunnel. I have no idea what the 'connect' line should have. When I run stunnel (clicking on desktop icon) I get: [.] Configuration successful [ ] Deallocating deployed section defaults [ ] Binding service [COMMONW10] [ ] Listening file descriptor created (FD=724) [ ] Setting accept socket options (FD=724) [ ] Option SO_EXCLUSIVEADDRUSE set on accept socket [.] Binding service [COMMONW10] to 127.0.0.1:3389: Permission denied (WSAEACCES) (10013) [!] Binding service [COMMONW10] failed [ ] Unbinding service [COMMONW10] [ ] Service [COMMONW10] closed [ ] Deallocating deployed section defaults [ ] Deallocating section [COMMONW10] [ ] Initializing inetd mode configuration [ ] Running on Windows 6.2 Server is down I'm assuming the "Permission denied" is because Remote Desktop is already listening on 3389. So, I'm stuck and feeling quite ignorant! Help appreciated. --Mark

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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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