June 2021 - stunnel-users

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 and rsyslog
by Yann RESCOURIO 28 Jun '21

28 Jun '21

Hello I use stunnel for rsyslog. And on the client equipment, I use also rsyslog queues for buffering in case of disconnection. But in case of reboot: * without stunnel, the buffered log messages are received on the rsyslog server * with stunnel, no buffered log messages are received on the rsyslog server On the client equipment, is it possible to refuse the local stunnel connections as long as the remote stunnel connection is down ? Regards Yann Rescourio

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FIPS 140-2 & Ubuntu Pro
by Patrick Kaeding 23 Jun '21

23 Jun '21

Hi I am trying to set up stunnel with FIPS 140-2 compliance. I found some discussion of this on this mailing list from many years ago, but I'm not sure how much of that is still relevant today. I am running Ubuntu Pro 18.04, with FIPS mode (including the userspace modules: https://security-certs.docs.ubuntu.com/en/fips) If I simply `apt-get install stunnel4`, I can create a config with `fips = yes`, and when I start it up, I see this line logged: 2021.06.23 15:45:24 LOG5[ui]: FIPS mode enabled Does this mean I am all set, without needing to compile anything from source? In this message (from almost a decade ago), it sounds like this might be the validation I need: > BTW: "fips" option is only available when stunnel is built with FIPS support. FIPS mode is also clearly logged on startup https://www.stunnel.org/pipermail/stunnel-users/2012-November/003963.html Or do I need to build stunnel from scratch, using my local openssl distribution? Thanks! -- Patrick Kaeding pkaeding(a)launchdarkly.com

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Number of tunnels open in Stunnel
by Moti Berger 21 Jun '21

21 Jun '21

Hi Is there a command I can run to get the current number of opened tunnels? I'm running Stunnel version 5.57. Thanks, Moti

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Help needed for email client
by Ian Huysman 15 Jun '21

15 Jun '21

Hi, I just tried to configure stunnel as proxy between an email client (Outlook Express) and the email server (SMTP and IMAP). The problem is that the connection times out in the client while synchronising the IMAP folders. But I can send emails from the client. This is my relatively basic configuration: [SMTP] client = yes accept = 25 connect = smtp.office365.com:587 protocol = smtp [IMAP] client = yes accept = 143 connect = outlook.office365.com:993 protocol = imap Any help would be greatly appreciated! Regards, Ian.

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SFTP over stunnel
by sameer_rm90＠hotmail.com 13 Jun '21

13 Jun '21

Hi, Is SFTP works over stunnel? If yes, how can configure it ?

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connect with hostname obtains incorrect IP address
by stunnel＠dsbconsulting.com 11 Jun '21

11 Jun '21

Hello everyone. I'm trying to use stunnel to forward smtp traffic from an old webcam to an smtp server that requires TLS. Everything works fine if I put the IP address of the smtp server in the connect= line, but if I put the hostname there, stunnel tries to connect to a seemingly random IP address. This happens using stunnel on Windows 10 and also on my router with OpenWrt (linux) Here is the config file: [smtp] client = yes accept = 192.0.0.1:25 ;connect = 199.193.7.228:465 connect = smtp.privateemil.com:465 And here is the failing part of the stunnel log file: 2021.06.11 18:24:54 LOG5[0]: Service [smtp] accepted connection from 192.0.0.111:49334 2021.06.11 18:24:54 LOG6[0]: s_connect: connecting 47.91.170.222:465 2021.06.11 18:24:54 LOG7[0]: s_connect: s_poll_wait 47.91.170.222:465: waiting 10 seconds 2021.06.11 18:24:54 LOG7[0]: FD=6 events=0x2001 revents=0x0 2021.06.11 18:24:54 LOG7[0]: FD=10 events=0x2005 revents=0x0 2021.06.11 18:25:04 LOG3[0]: s_connect: s_poll_wait 47.91.170.222:465: TIMEOUTconnect exceeded Here is the result of ping for the smtp server: PING smtp.privateemail.com (199.193.7.228): 56 data bytes 64 bytes from 199.193.7.228: seq=0 ttl=237 time=103.059 ms

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