October 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 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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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 17 Oct '20

17 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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Re: [stunnel-users] stunnel-users Digest, Vol 183, Issue 4
by Brent Kimberley 26 Oct '19

26 Oct '19

Chris.Does this help? https://stackoverflow.com/questions/40454338/no-shared-cipher-at-ssl-accept… If you can rule out libraries like OpenSSL, then look at your config + initial setup exchange. Date: Fri, 25 Oct 2019 11:11:54 -0400 From: Christopher Schultz <chris(a)christopherschultz.net> Subject: Re: [stunnel-users] Strange connection failure in one environmentOn 10/25/19 10:09, Christopher Schultz wrote: > All, > > I've been using stunnel in two environments (dev, prod) for a long time > without any problems. Recently, my dev environment started acting funny > and I can't connect to it from outside the box. > > Can someone take a look and let me know if you have any suggestions for > where to look for a problem? > > Both environments have the following things in common: > > 1. Hosted in Amazon EC2, no load-balancer in the way > 2. Configuration requires client-certificate to connect > 3. All certificates are valid, self-signed, and properly-trusted by both > sides > 4. TLS configuration has been locked-down to TLSv1.2, selected cipher > suites, FIPS mode=off > 5. All versions are the same: stunnel 4.56 w/OpenSSL 1.0.2k-fips > > The production (working) environment happens to be i686 and the > development environment happens to be x86-86, but I don't believe that > is relevant. > > When I use e.g. "openssl s_client" to connect to the production > environment and I *do not* provide a client certificate, I am able to > perform the initial TLS handshake, get a cipher suite negotiated, etc. > and then the connection fails because I didn't provide the client > certificate, of course. I *can* see in the handshake the list of allowed > client certificates. > > When I do the same in development, I get a handshake failure. No allowed > client certificates are shown. No nothing. > > If I connect on localhost to the dev server, I get what I'm expecting: > allowed client certificates are listed, connection is closed because I'm > not using the client certificate. Connecting from another host gets my a > handshake failure. > > Again, there are no load-balancers or anything between the outside and > the EC2 instance. I'm connecting as directly as it's possible to > connect. The box definitely allows incoming connections on the port I'm > trying to use; the AWS security group is configured correctly. > > I have tried dropping ALL security configuration on the dev server's > stunnel.conf such as client-cert requirements, TLS protocols, cipher > suites, etc. and I get the same behavior every time. I'm starting to > think that it has nothing to do with my stunnel.conf configuration at > all, but I'm at a loss as to where to look, next. > > Any ideas? Some more information: 0. The error I get on the client is "handshake failure" and the stunnel server drops this log message: SSL_accept: 1408A0C1: error:1408A0C1:SSL routines:ssl3_get_client_hello:no shared cipher Note that I have disabled all but TLSv1.2 on the server. Removing this restriction does not change the behavior. 1. I have multiple stunnel configuration files on this server. Actually, I have 4 of them. Connections to ports defined in 2 of these files are not connecting successfully. Connections to ports defined in the OTHER two files *are* connecting successfully. The configurations seem to follow a pattern: those using RSA certificates as the server-certificate are working as expected, while those with EC server-certificate are failing. When I say "working" versus "failing", I mean that this command will give me a cipher suite and master key, but still drop the connection because I'm not providing a client-certificate for these tests: $ openssl s_client -connect host:port 2. I have a Java-based service that *is* able to connect through this stunnel instance just fine. It's running on a recent version of Java 8. My CLI client (not OpenSSL) is also running the same version. My CLI client cannot connect. *weird* In both cases, I am using EC client certificates, but the certificates are different from each other. Both of these certificates are trusted by the server. 3. When using OpenSSL 1.0.2t, I *can* connect, get the list of acceptable client certificates, etc. even without providing a client certificate. When using OpenSSL 1.1.1d, I can *not* connect. So perhaps the inside/outside networking thing I was thinking the problem might be is incorrect. AFAIK, both versions of OpenSSL should be able to use EC certificates and cipher suites. Thanks, -chris

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Strange connection failure in one environment
by Christopher Schultz 26 Oct '19

26 Oct '19

All, I've been using stunnel in two environments (dev, prod) for a long time without any problems. Recently, my dev environment started acting funny and I can't connect to it from outside the box. Can someone take a look and let me know if you have any suggestions for where to look for a problem? Both environments have the following things in common: 1. Hosted in Amazon EC2, no load-balancer in the way 2. Configuration requires client-certificate to connect 3. All certificates are valid, self-signed, and properly-trusted by both sides 4. TLS configuration has been locked-down to TLSv1.2, selected cipher suites, FIPS mode=off 5. All versions are the same: stunnel 4.56 w/OpenSSL 1.0.2k-fips The production (working) environment happens to be i686 and the development environment happens to be x86-86, but I don't believe that is relevant. When I use e.g. "openssl s_client" to connect to the production environment and I *do not* provide a client certificate, I am able to perform the initial TLS handshake, get a cipher suite negotiated, etc. and then the connection fails because I didn't provide the client certificate, of course. I *can* see in the handshake the list of allowed client certificates. When I do the same in development, I get a handshake failure. No allowed client certificates are shown. No nothing. If I connect on localhost to the dev server, I get what I'm expecting: allowed client certificates are listed, connection is closed because I'm not using the client certificate. Connecting from another host gets my a handshake failure. Again, there are no load-balancers or anything between the outside and the EC2 instance. I'm connecting as directly as it's possible to connect. The box definitely allows incoming connections on the port I'm trying to use; the AWS security group is configured correctly. I have tried dropping ALL security configuration on the dev server's stunnel.conf such as client-cert requirements, TLS protocols, cipher suites, etc. and I get the same behavior every time. I'm starting to think that it has nothing to do with my stunnel.conf configuration at all, but I'm at a loss as to where to look, next. Any ideas? -chris

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ssl offloading with stunnel
by simona vittori 23 Oct '19

23 Oct '19

Hello,Is it possible to have the following architecture with stunnel? stunnel client --> balancer --> db server Balancer doesn't have stunnel product installed on it. It receives encrypted packages from stunnel client and redirect clear traffico to DB server. Is it possible to realize this configuration? Thank a lot. Regards Simona

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stunnel : user identification in mutual auth
by Denis Polushin 23 Oct '19

23 Oct '19

Hi All, Haven't found the answer for this issue. The scheme is : TLS-client <==tls==> stunnel-server <==open==> App-server In user session stunnel-server perform authorization for client with its certificate (verify=2) and send request further to App-server. How does App-server can identify user in this session? To grand permissions. Ideally it would be good to know CN or EKU of user certificate. Is it possible? Thanks a lot!! Denis

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