July 2020 - 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:[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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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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TLS1.0 fallback when only TLS1.2 allowed
by Wojciech Machula 31 Aug '20

31 Aug '20

So I've configured my stunnel to only use TLS1.2 and usually works ok. However when client gets some bad L7 response it send a TCP RST, after which all subsequent stunnel TLS Client Hellos are some hybrid of TLS1.0/TLS1.2, as can be seen in tshark output below. Once I restart the whole stunnel process subsequent TLS handshakes work fine using TLS1.2, until the next client RST is received. $ stunnel -version stunnel 4.56 on x86_64-redhat-linux-gnu platform $ cat /etc/centos-release CentOS Linux release 7.8.2003 (Core) $cat /etc/stunnel/dsr2rtcg-stunnel.conf output = /var/log/stunnel pid = /etc/stunnel/stunnel.pid socket = l:TCP_NODELAY=1 socket = r:TCP_NODELAY=1 [poc] cert = /etc/pki/tls/certs/stunnel/aaa.crt key = /etc/pki/tls/private/stunnel/aaa.key CAfile = /etc/pki/tls/certs/stunnel/bbb.crt client = yes sslVersion = TLSv1.2 options = NO_TLSv1 accept = 172.18.180.78:45154 connect = 10.74.0.196:45154 ciphers = TLSv1.2+HIGH:!aNULL $ tshark -nn -V -d tcp.port==45154,ssl -r 20200729_09:42:44-port45154.pcap -2R "ssl.handshake" -c 1 | grep -i tls -B3 Secure Sockets Layer SSL Record Layer: Handshake Protocol: Client Hello Content Type: Handshake (22) Version: TLS 1.0 (0x0301) -- Handshake Protocol: Client Hello Handshake Type: Client Hello (1) Length: 1610 Version: TLS 1.2 (0x0303)

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Getting incoming Exchange online (Office 365) emails to go to port 110 and not 995
by Brent Kimberley 23 Jul '20

23 Jul '20

Office365 IMAP4S + POP3S is dropping legacy authentication in favour of OAUTH2.0 authentication -- effective October 2020. (Some may have longer.) How do you you plan to migrate to authentication? Do you plan to upgrade your client(s) or inject an OAUTH2.0 transparent proxy ? ---------------------------------------------------------------------- Message: 1 Date: Thu, 23 Jul 2020 01:22:06 +0000 From: Mel Gilbert <m.gilbert(a)baymedicalgroup.com.au> To: "stunnel-users(a)stunnel.org" <stunnel-users(a)stunnel.org> Subject: Re: [stunnel-users] Getting incoming Exchange online (Office 365) emails to go to port 110 and not 995 Message-ID: <SY4P282MB074766F32238B92A3D951499C1760(a)SY4P282MB0747.AUSP282.PROD.OUTLOOK.COM> Content-Type: text/plain; charset="us-ascii" Hi Trying to get an application with inbuilt email to receive emails using POP and port 110. However we use Office 365 and I have tried below config but it is not working. I want people to send email to an Exchange Online Account port 995 and it gets forwarded on to the email app on port 110 client = yes output = stunnel-log.txt debug=7 taskbar=yes [POP3 Incoming] accept = 110 connect = Outlook.office365.com:995 cert = stunnel.pem [SMTP Outgoing] protocol = smtp accept = 25 connect = smtp.office365.com:587 cert = stunnel.pem The outgoing email works fine using SMTP relay that I've set up on Office 365 but cant get the incoming emails to work. Any help would be appreciated Thanks Mel

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Re: [stunnel-users] Getting incoming Exchange online (Office 365) emails to go to port 110 and not 995
by Mel Gilbert 23 Jul '20

23 Jul '20

Hi Trying to get an application with inbuilt email to receive emails using POP and port 110. However we use Office 365 and I have tried below config but it is not working. I want people to send email to an Exchange Online Account port 995 and it gets forwarded on to the email app on port 110 client = yes output = stunnel-log.txt debug=7 taskbar=yes [POP3 Incoming] accept = 110 connect = Outlook.office365.com:995 cert = stunnel.pem [SMTP Outgoing] protocol = smtp accept = 25 connect = smtp.office365.com:587 cert = stunnel.pem The outgoing email works fine using SMTP relay that I've set up on Office 365 but cant get the incoming emails to work. Any help would be appreciated Thanks Mel

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Transparent Proxy help.
by Steven Relf 21 Jul '20

21 Jul '20

Hello List, I am working on a small project where I need to encrypt nfs traffic, and Stunnel looks to be ideal, the only issue I'm having is getting the transparent part to work I have a client machine, running stunnel config below #GLOBAL####################################################### sslVersion = TLSv1.2 TIMEOUTidle = 600 renegotiation = no FIPS = no options = NO_SSLv2 options = NO_SSLv3 options = SINGLE_DH_USE options = SINGLE_ECDH_USE options = CIPHER_SERVER_PREFERENCE syslog = yes debug = 7 ;chroot = /var/empty/stunnel libwrap = yes service = 3d-nfsd curve = secp521r1 #CREDENTIALS################################################## verify = 4 CAfile = /etc/stunnel/nfs-tls.pem cert = /etc/stunnel/nfs-tls.pem #ROLE######################################################### client = yes connect = fqdn:2363 and the client which is running ontop of the nfs-ganesha server config below #GLOBAL####################################################### TIMEOUTidle = 600 renegotiation = no FIPS = no options = NO_SSLv2 options = NO_SSLv3 options = SINGLE_DH_USE options = SINGLE_ECDH_USE options = CIPHER_SERVER_PREFERENCE syslog = yes debug = 7 setuid = nobody setgid = nobody chroot = /var/empty/stunnel libwrap = yes service = MC-nfsd ; cd /var/empty; mkdir -p stunnel/etc; cd stunnel/etc; ; echo 'MC-nfsd: ALL EXCEPT 5.6.7.8' >> hosts.deny; ; chcon -t stunnel_etc_t hosts.deny curve = secp521r1 #CREDENTIALS################################################## verify = 4 CAfile = /etc/stunnel/nfs-tls.pem cert = /etc/stunnel/nfs-tls.pem #ROLE######################################################### connect = 127.0.0.1:2049 I have had a look through the documentation and I believe I need to set transparent = source on the client side, and then set some ip tables firewall rules. Does anyone have a guide, or some advice on how to get this to work. Generally what happens if I set the firewall rules, on the client, and set the transparent to source I just get connection closed by remote host. I never actually see the traffic leave the client host. To confirm, when not using transparent everything works correctly, accept the server side sees the connection coming from 127.0.0.1 Thanks Rgds Steve. The future has already arrived. It's just not evenly distributed yet - William Gibson Steven Relf - Technical Authority: Cloud Native Infrastructure srelf(a)ukcloud.com +44 1252 936019 / +44 7500 085 864 www.ukcloud.com A8, Cody Technology Park, Ively Road, Farnborough, GU14 0LX Notice: This message contains information that may be privileged or confidential and is the property of UKCloud Ltd. It is intended only for the person to whom it is addressed. If you are not the intended recipient, you are not authorised to read, print, retain, copy, disseminate, distribute, or use this message or any part thereof. If you receive this message in error, please notify the sender immediately and delete all copies of this message. UKCloud reserves the right to monitor all e-mail communications through its networks. UKCloud Ltd is registered in England and Wales: Company No: 07619797. Registered office: Hartham Park, Hartham, Corsham, Wiltshire SN13 0RP.

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