February 2019 - 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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Stunnel 4 failing to connect to gmail
by Asif Iqbal 11 Dec '20

11 Dec '20

I am faling to connect to gmail. Not sure what that bind error means. iqbala@ghar:~$ sudo stunnel4 2008.12.15 13:53:17 LOG7[3839:3083650736]: Snagged 64 random bytes from /home/iqbala/.rnd 2008.12.15 13:53:17 LOG7[3839:3083650736]: Wrote 1024 new random bytes to /home/iqbala/.rnd 2008.12.15 13:53:17 LOG7[3839:3083650736]: RAND_status claims sufficient entropy for the PRNG 2008.12.15 13:53:17 LOG7[3839:3083650736]: PRNG seeded successfully 2008.12.15 13:53:17 LOG7[3839:3083650736]: Certificate: /etc/stunnel/stunnel.pem 2008.12.15 13:53:17 LOG7[3839:3083650736]: Certificate loaded 2008.12.15 13:53:17 LOG7[3839:3083650736]: Key file: /etc/stunnel/stunnel.pem 2008.12.15 13:53:17 LOG7[3839:3083650736]: Private key loaded 2008.12.15 13:53:17 LOG7[3839:3083650736]: SSL context initialized for service ssmtp 2008.12.15 13:53:17 LOG5[3839:3083650736]: stunnel 4.22 on i486-pc-linux-gnu with OpenSSL 0.9.8g 19 Oct 2007 2008.12.15 13:53:17 LOG5[3839:3083650736]: Threading:PTHREAD SSL:ENGINE Sockets:POLL,IPv6 Auth:LIBWRAP 2008.12.15 13:53:17 LOG6[3839:3083650736]: file ulimit = 1024 (can be changed with 'ulimit -n') 2008.12.15 13:53:17 LOG6[3839:3083650736]: poll() used - no FD_SETSIZE limit for file descriptors 2008.12.15 13:53:17 LOG5[3839:3083650736]: 500 clients allowed 2008.12.15 13:53:17 LOG7[3839:3083650736]: FD 10 in non-blocking mode 2008.12.15 13:53:17 LOG7[3839:3083650736]: FD 11 in non-blocking mode 2008.12.15 13:53:17 LOG7[3839:3083650736]: FD 12 in non-blocking mode 2008.12.15 13:53:17 LOG7[3839:3083650736]: SO_REUSEADDR option set on accept socket 2008.12.15 13:53:17 LOG3[3839:3083650736]: Error binding ssmtp to 74.125.93.111:587 2008.12.15 13:53:17 LOG3[3839:3083650736]: bind: Cannot assign requested address (99) Here is how my conf file looks like iqbala@ghar:~$ cat /etc/stunnel/stunnel.conf | egrep -v "^;|^$" cert = /etc/stunnel/stunnel.pem foreground = yes sslVersion = SSLv3 chroot = /var/lib/stunnel4/ setuid = stunnel4 setgid = stunnel4 pid = /stunnel4.pid socket = l:TCP_NODELAY=1 socket = r:TCP_NODELAY=1 debug = 7 output = /var/log/stunnel4/stunnel.log client = yes [ssmtp] accept = smtp.gmail.com:587 connect = 25 Asif Iqbal PGP Key: 0xE62693C5 KeyServer: pgp.mit.edu

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Stunnel & Gmail security
by BOXI31 TEST 16 Oct '20

16 Oct '20

Hi all, To make "Stunnel 5.31" work with Gmail, I have to go in security settings of Gmail and "allow less secure apps to access my account". Is it mandatory ? Is it possible to set Stunnel to access Gmail without lowering it security level ? How ? I checked in log file TLS v1.2 is used by Stunnel but Gmail still consider it as a "less secure app." ! Regards, Steve

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(no subject)
by Vijay Raghavan P 05 Mar '19

05 Mar '19

Hi, I have to create tunnel between server and client. Client have proxy configured in between. So i use below in /etc/stunnel/stunnel.config pid = /var/run/stunnel.pid cert = /home/client.crt key = /home/client.key options = NO_SSLv2 debug = 7 output = /var/log/stunnel4/stunnel.log client = yes CAfile=/home/**chain.pem verify=2 [test] protocol = connect accept = 127.0.0.1:10000 protocolHost = server.xxxx.com:443 connect = <PROXYIP>:<PROXY port> protocolUsername = user1 protocolPassword = password protocolAuthentication = Basic then i bring up the service. With above configuration connection works file. Now i don't want proxy password to be clear text in this case. Any pointers plz Thanks, Vj

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Issue with NTLM authorisation
by Vijay Raghavan P 01 Mar '19

01 Mar '19

Hi, I have to create tunnel between server and client. Client have proxy configured in between. So i use below in /etc/stunnel/stunnel.config. User name and password is correct pid = /var/run/stunnel.pid cert = /home/client.crt key = /home/client.key options = NO_SSLv2 debug = 7 output = /var/log/stunnel4/stunnel.log client = yes CAfile=/home/**chain.pem verify=2 [test] protocol = connect accept = 127.0.0.1:10000 protocolHost = host.vmj.com:443 connect = <PROXYIP>:<PROXY port> protocolUsername = vmj.com\user1 protocolPassword = VMJTEST!123 protocolAuthentication = NTLM In stunnel.log, i can see below error 2019.02.28 18:36:50 LOG6[2103:140737354032896]: Client-mode connect protocol negotiations started 2019.02.28 18:36:50 LOG7[2103:140737354032896]: -> CONNECT host.vmj.com:443 HTTP/1.1 2019.02.28 18:36:50 LOG7[2103:140737354032896]: -> Host: host.vmj.com:443 2019.02.28 18:36:50 LOG7[2103:140737354032896]: -> Proxy-Connection: keep-alive 2019.02.28 18:36:50 LOG7[2103:140737354032896]: -> Proxy-Authorization: NTLM TlRMTVNTUAABAAAAAgIAAA== 2019.02.28 18:36:50 LOG7[2103:140737354032896]: -> 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- HTTP/1.1 407 Proxy Authentication Required 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Server: squid/3.3.8 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Mime-Version: 1.0 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Date: Thu, 28 Feb 2019 18:36:33 GMT 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Content-Type: text/html 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Content-Length: 3285 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- X-Squid-Error: ERR_CACHE_ACCESS_DENIED 0 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Vary: Accept-Language 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Content-Language: en 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Proxy-Authenticate: NTLM TlRMTVNTUAACAAAAAAAAADgAAAACAgACueAMGSlaSZ0AAAAAAAAAAAAAAAA4AAAABgEAAAAAAA8= 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- X-Cache: MISS from squidproxy.vmj.com 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- X-Cache-Lookup: NONE from squidproxy.vmj.com:3128 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Via: 1.1 squidproxy.vmj.com (squid/3.3.8) 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Connection: keep-alive 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- 2019.02.28 18:36:50 LOG7[2103:140737354032896]: -> CONNECT host.vmj.com:443 HTTP/1.1 2019.02.28 18:36:50 LOG7[2103:140737354032896]: -> Host: host.vmj.com:443 2019.02.28 18:36:50 LOG7[2103:140737354032896]: -> Proxy-Authorization: NTLM TlRMTVNTUAADAAAAAAAAAGcAAAAYABgAQAAAAAAAAABnAAAADwAPAFgAAAAAAAAAZwAAAAAAAABnAAAAAgIAAAGbqH5v5ML8msrfm3R1yDBsS+ai3ldihnZybmkuY29tXGJoYXJ0aQ== 2019.02.28 18:36:50 LOG7[2103:140737354032896]: -> 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- HTTP/1.1 407 Proxy Authentication Required 2019.02.28 18:36:50 LOG3[2103:140737354032896]: CONNECT request rejected 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Server: squid/3.3.8 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Mime-Version: 1.0 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Date: Thu, 28 Feb 2019 18:36:33 GMT 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Content-Type: text/html 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Content-Length: 3363 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- X-Squid-Error: ERR_CACHE_ACCESS_DENIED 0 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Vary: Accept-Language 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Content-Language: en 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Proxy-Authenticate: NTLM 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- X-Cache: MISS from squidproxy.vmj.com 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- X-Cache-Lookup: NONE from squidproxy.vmj.com:3128 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Via: 1.1 squidproxy.vmj.com (squid/3.3.8) 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- Connection: keep-alive 2019.02.28 18:36:50 LOG7[2103:140737354032896]: <- 2019.02.28 18:36:50 LOG5[2103:140737354032896]: Connection reset: 0 byte(s) sent to SSL, 0 byte(s) sent to socket 2019.02.28 18:36:50 LOG7[2103:140737354032896]: Remote socket (FD=14) closed 2019.02.28 18:36:50 LOG7[2103:140737354032896]: Local socket (FD=3) closed 2019.02.28 18:36:50 LOG7[2103:140737354032896]: Service [test] finished (0 left) If i try with basic authentication it works fine. Its urgent , can some one help me out. Thanks, Vj

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Tunnel from win32 to Unix
by Eetu Pikkarainen 26 Feb '19

26 Feb '19

Hi, I am a totally newbie with this. We have intranet system in Windows Server (32bit) which reads a database (Oracle) situated in Unix machine via a tunnel made by Putty.exe. That works well except that the connection gets lost every now and then and it must be manually logged in every time. So I decided to try stunnel which we used earlier to read email from email server. However I cannot set the connection successfully. This is what I have tried now (among many other alternatives): [Kanto2] client = yes accept = 127.0.0.1:1501 connect = kanto2.oulu.fi:22 protocolUsername = <username> protocolPassword = <password> stunnel reads the configuration OK except this notification: [:] Service [Kanto2] needs authentication to prevent MITM attacks but when the database is tried to read happens this: 2019.02.18 13:32:30 LOG5[1]: Service [Kanto2] accepted connection from 127.0.0.1:64699 2019.02.18 13:32:30 LOG5[1]: s_connect: connected 130.231.240.100:22 2019.02.18 13:32:30 LOG5[1]: Service [Kanto2] connected remote server from 130.231.241.250:64700 2019.02.18 13:32:30 LOG3[1]: SSL_connect: 140770FC: error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol 2019.02.18 13:32:30 LOG5[1]: Connection reset: 0 byte(s) sent to TLS, 0 byte(s) sent to socket I have tried different protocol alternatives with no help. What could be the problem? Is this kind of use even possible? thanks Eetu Pikkarainen PhD (Ed.), (Title of) Adjunct Prof., University Lecturer (in Education) Faculty of Education, University of Oulu, Finland Research Group: https://wiki.oulu.fi/display/theored Latest publications: Semiotic Theory of Learning: New Perspectives in the Philosophy of Education. By Andrew Stables, Winfried Nöth, Alin Olteanu, Sébastien Pesce and Eetu Pikkarainen https://www.taylorfrancis.com/books/e/9781351725170 Schools in Transition: Linking Past, Present, and Future in Educational Practice. Edited by Pauli Siljander, Kimmo Kontio and Eetu Pikkarainen https://www.sensepublishers.com/catalogs/bookseries/other-books/schools-in-…

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Stunnel 3.50 Win - CAPI stopped working
by pepak＠seznam.cz 18 Feb '19

18 Feb '19

Hello, I have encountered a bug in Stunnel version 3.50. I have a setup with two computers (Server and Client) connected using Stunnel. The client is using a hardware token through the CAPI engine to authenticate itself to a server, using a config file: ----- fips = no taskbar = yes options = NO_SSLv2 options = NO_SSLv3 sslVersion = TLSv1.2 engine = capi [my-server] client = yes accept = 22 connect = my.server.com:1234 requireCert = yes verifyChain = yes verifyPeer = yes CAfile = my-cert-chain.pem engineId = capi ----- This setup works perfectly in Stunnel 3.49: When I try to connect to localhost:22, I receive a request to select a certificate and enter its PIN, and if successful, a connection to my server is established. In Stunnel 3.50, the connection fails to complete. The Stunnel log shows: LOG5[0]: Service [my-server] accepted connection from 127.0.0.1:49713 LOG5[0]: s_connect: connected 1.2.3.4:1234 LOG5[0]: Service [my-server] connected remote server from 10.11.12.13:49714 LOG5[0]: Certificate accepted at depth=0: CN=My server LOG3[0]: error queue: 141F0006: error:141F0006:SSL routines:tls_construct_cert_verify:EVP lib LOG3[0]: SSL_connect: 8006F074: error:8006F074:lib(128):capi_rsa_priv_enc:function not supported LOG5[0]: Connection reset: 0 byte(s) sent to TLS, 0 byte(s) sent to socket However, if I change the engine to the default one and use a certificate in file, everything works fine. That suggests to me that the problem lies in the Stunnel's CAPI engine library. It is quite possible the problem is caused by the CAPI engine itself. I was experimenting with OpenSSL 1.1.1a some time back, trying to compile my own library files, and I just couldn't to get CAPI to work at all - the libraries themselves compiled OK and worked fine, but the CAPI engine just wouldn't work (while it was OK with OpenSSL 1.0.2q); the only way I could get CAPI to work with OpenSSL 1.1.1a was to use the 1.1.1a libraries and the 1.0.2q capi.dll. However, I am far from an expert on compiling OpenSSL, so I may have gotten it completely wrong. Could someone please verify that their CAPI engine is working with Stunnel? Also, it may be worth trying to compile a 64bit CAPI.dll from version 1.0.2q just to see if it might start working - in that case, a bug report to OpenSSL may be in order. Thanks. pepak

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