November 2022 - 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:[email protected]] 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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Setup and Installing stunnel on windows wsl2 Ubuntu
by adamsaltlake＠hotmail.com 25 Nov '22

25 Nov '22

I am new to stunnel and have been struggling for weeks to get it to work on windows wsl2 ubuntu; it keep failing with pid error "You should check that you have specified the pid= in you configuration file" any idea is welcome

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Self signed certificate check
by Bob Bob 20 Nov '22

20 Nov '22

Hi, I have two Windows based stations with one hosting a specific service. Stunnel is used to create a secure connection. As stated on the auth page, I have implemented PSK to prevent MITM Attack but also as a way to authenticate connections and limit who can connect to the server. I would like to add an extra layer of security by having the Server only accept connections when the client submits a pre-agreed self cert. verifyPeer does not seem to work with self certificate. I would like to end up with PSK + certificate check. Is there a way to achieve that with self certificate on Stunnel? Thanks.

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Windows 10 Pro - StartService: error 1053
by jason99si＠gmail.com 11 Nov '22

11 Nov '22

I'm installing stunnel for a second time. I'm using it for Blue Iris on a Windows 10 Pro machine. I'm using stunnel 5.67 on Win64. GUI shows "Configuration successful". I've tried uninstalling and reinstalling numerous times. When I run stunnel Service Start I receive a dialog box that says: stunnel 5.67 on Win64 (not configured) StartService: error 1053: The service did not respond to the start or control request in a timely fashion Can anyone help?

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Two certificates on same connection
by perisnagini＠gmail.com 07 Nov '22

07 Nov '22

hi, I am into implementations and generally use stunnel with a certification provided by our third party connections in stunnel for encryption/ decryption both ways. Recently we had a query from one of our vendors stating we must use one cert to encrypt which they will decrypt using the key provided by us and they will encrypt which must be decrypted using the key provided. Keeping it simple we have below: Client Key - clt.pem Client cert - clt.cer Vendor key - vndr.pem our ca certs - ca-cert.pem Could anyone help me in understanding how do I leverage vendor key for decrypting and clt key for encrypting in stunnel.conf using the above certs. Many Thanks.

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error:0A000126:SSL routines::unexpected eof while reading
by sburke＠unitedelectric.com 07 Nov '22

07 Nov '22

Hello, I am trying to get a system notification email back up and running after google disabled the "use less secure apps" functionality in the Gmail platform. I have set up the Gmail account to use an app password which I assigned to the system that was sending emails before this change. It appears the system is now connecting to Stunnel running on a windows 10 machine and Stunnel is making the connection with the Gmail server again, but no email actually gets sent out. I am running Stunnel 5.66 Here is the configuration currently: [gmail-smtp] client = yes accept = 25 connect = smtp.gmail.com:465 verifyChain = yes CAfile = ca-certs.pem checkHost = smtp.Gmail.com OCSPaia = yes Here is a copy of the log file: 2022.09.20 07:40:49 LOG5[0]: Service [gmail-smtp] accepted connection from 192.168.100.200:56399 2022.09.20 07:40:49 LOG5[0]: s_connect: connected 74.125.138.109:465 2022.09.20 07:40:49 LOG5[0]: Service [gmail-smtp] connected remote server from 172.16.4.220:60367 2022.09.20 07:40:49 LOG5[0]: OCSP: Connecting the AIA responder "http://ocsp.pki.goog/gtsr1" 2022.09.20 07:40:50 LOG5[0]: s_connect: connected 142.251.40.67:80 2022.09.20 07:40:50 LOG5[0]: OCSP: Certificate accepted 2022.09.20 07:40:50 LOG5[0]: OCSP: Connecting the AIA responder "http://ocsp.pki.goog/gts1c3" 2022.09.20 07:40:50 LOG5[0]: s_connect: connected 142.251.40.67:80 2022.09.20 07:40:50 LOG5[0]: OCSP: Certificate accepted 2022.09.20 07:40:50 LOG5[0]: Certificate accepted at depth=0: CN=smtp.gmail.com 2022.09.20 07:40:51 LOG3[0]: SSL_read: ssl/record/rec_layer_s3.c:308: error:0A000126:SSL routines::unexpected eof while reading 2022.09.20 07:40:51 LOG5[0]: Connection reset: 92 byte(s) sent to TLS, 620 byte(s) sent to socket Is this something I can remedy from the configuration, or is this something that requires modification on the email server side? Thank you sean

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