stunnel-users

3306 discussions

Version 4.29: First connection fails with "Unexpected socket close (read_blocking)"
by Matthew 26 Feb '16

26 Feb '16

Hi, I am experiencing an issue with version 4.29, which is the version available on yum for centos6. I am getting the following error: "Unexpected socket close (read_blocking)". This error only occurs once per stunnel instance upon the first connection only. More recent versions of stunnel do not have this problem, but I am hoping to work around this issue on the default version for this OS. My hosts.allow and hosts.deny files are both empty. I have tried adding my services to hosts.allow, but it did not have any noticeble effect. This is the version that I am using (installed with "yum install stunnel"): $ stunnel -version stunnel 4.29 on x86_64-redhat-linux-gnu with OpenSSL 1.0.1e-fips 11 Feb 2013 Threading:PTHREAD SSL:ENGINE,FIPS Sockets:POLL,IPv6 Auth:LIBWRAP Global options debug = 5 pid = /var/run/stunnel.pid RNDbytes = 64 RNDfile = /dev/urandom RNDoverwrite = yes Service-level options cert = /etc/stunnel/stunnel.pem ciphers = FIPS key = /etc/stunnel/stunnel.pem session = 300 seconds stack = 65536 bytes sslVersion = TLSv1 TIMEOUTbusy = 300 seconds TIMEOUTclose = 60 seconds TIMEOUTconnect = 10 seconds TIMEOUTidle = 43200 seconds verify = none This is what my demonstration setup looks like: nc_client --TCP--> stunnel_client (2000) --SSL--> stunnel_server (2100) --TCP--> nc_server (2200) Steps to reproduce: (1) Start the netcat TCP server. $ nc -l 2200 (2) Leave the server open and open a new terminal for the rest of the commands. (3) Create “client_config.txt” with the following contents: pid = /tmp/client_stunnel.pid debug = 7 output = /tmp/client_stunnel.log client = yes ciphers = ALL fips = no foreground = no [CLIENT_PROXY_0] accept = 0.0.0.0:2000 connect = 127.0.0.1:2100 (4) Create “server_config.txt” with the following contents: pid = /tmp/server_stunnel.pid debug = 7 output = /tmp/server_stunnel.log client = no ciphers = ALL fips = no cert = /tmp/server_stunnel.pem foreground = no [SVR_PROXY_0] accept = 0.0.0.0:2100 connect = 127.0.0.1:2200 (4) Start the stunnel client: $ cat client_config.txt | stunnel -fd 0 (5) Start the stunnel server: $ cat server_config.txt | stunnel -fd 0 (6) Send three sequential messages through stunnel to the netcat server: $ echo "Test 1" | nc 127.0.0.1 2000 $ echo "Test 2" | nc 127.0.0.1 2000 $ echo "Test 3" | nc 127.0.0.1 2000 (7) You should see only “Test 3” appear at the netcat server. “Test 1” will have failed to pass from the stunnel client to the stunnel server and the log will report an "Unexpected socket close (read_blocking)” error. “Test 2” is not the first connection for the stunnel client, so it will pass through to the stunnel server successfully. But because it is the first connection for the stunnel server, it will fail there with the same error. “Test 3” is not the first connection for either the stunnel client or stunnel server, so it will make it through successfully to the netcat server. All subsequent connections will work. Basically my question is: Is there any way to make this setup work on the first connection with version 4.29, or is a new version necessary? Thanks, Matthew

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How to use stunnel as a HTTPS to HTTPS reverse proxy
by Claudio Beretta 26 Feb '16

26 Feb '16

I'd like Stunnel to act as a reverse proxy that accepts TLS 1.0 and TLS 1.2 for https://example.com and then forwards the traffic to https://example.net, another web server that only accepts TLS 1.2 browser --TLS 1.0 or 1.2--> Stunnel --TLS 1.2--> Web App The browser should have no idea that example.net even exists (only example.com certificate will be presented to the browser). Is this something Stunnel can do? This is what I got so far: cert = example.com.pem ;stunnel.pem [proxy1] client = yes accept = 10.100.4.179:443 connect = localhost:54323 CAfile = sca.server1.crt.pem ;verify = 2 [proxy2] client = no accept = localhost:54323 connect = example.net:443 ;CAfile = SymantecClass3EVSSLCA-G3.pem example.com.pem contains the public and decrypted private key for example.com sca.server1.crt.pem contains the intermediate and root certificates of the CA that issues the example.com.pem certificate It partially works: the browser shows example.com in the address bad and the content of example.net, but the certificate that is returned is from example.net What am I doing wrong? Or do you have other recommendations to get something like this working on Windows Server 2008 R2? (IIS + Application Request Routing + URL Rewrite won't work: TLS1.2 is not properly supported) Thank you Claudio

3 4

Usint Stunnel in combination with tinyproxy and PSK
by Christoph Malin 26 Feb '16

26 Feb '16

Hello, I have tinyproxy running on my server. Now I would like to add stunnel with a pres shared key (username, password combination). Is it possible to use this combination as a Proxy on my normal web browser e.g. firefox? So that stunnel ist only used on server side? greetings Christoph

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User-agent string
by Josh Rabinowitz 22 Feb '16

22 Feb '16

Is there a way to force stunnel to use a specific user-agent string? I have mulled through documentation, this list, and other places with no results. The reason I ask, is the proxy I am going through is super strict, well not really. It will accept 'lynx' as a user-agent (among others), but it needs something. I cannot figure out how to tell stunnel to use something like this. 5.30 on both ends, here is debug 7 from the client (IPs changed for privacy) after a config reload and ssh attempt: 2016.02.22 09:22:08 LOG5[main]: Reading configuration from file stunnel.conf 2016.02.22 09:22:08 LOG5[main]: UTF-8 byte order mark not detected 2016.02.22 09:22:08 LOG5[main]: FIPS mode disabled 2016.02.22 09:22:08 LOG5[main]: Configuration successful 2016.02.22 09:22:15 LOG7[4]: Service [ssh] started 2016.02.22 09:22:15 LOG5[4]: Service [ssh] accepted connection from 127.0.0.1:56690 2016.02.22 09:22:15 LOG6[4]: failover: round-robin, starting at entry #1 2016.02.22 09:22:15 LOG6[4]: s_connect: connecting [webproxyIP]:8080 2016.02.22 09:22:15 LOG7[4]: s_connect: s_poll_wait [webproxyIP]:8080: waiting 10 seconds 2016.02.22 09:22:15 LOG5[4]: s_connect: connected [webproxyIP]:8080 2016.02.22 09:22:15 LOG5[4]: Service [ssh] connected remote server from [clientIP]:56691 2016.02.22 09:22:15 LOG7[4]: Remote descriptor (FD=844) initialized 2016.02.22 09:22:15 LOG7[4]: -> CONNECT [remoteIP]:443 HTTP/1.1 2016.02.22 09:22:15 LOG7[4]: -> Host: [remoteIP]:443 2016.02.22 09:22:15 LOG7[4]: -> 2016.02.22 09:22:15 LOG7[4]: <- HTTP/1.1 403 Forbidden 2016.02.22 09:22:15 LOG3[4]: CONNECT request rejected 2016.02.22 09:22:15 LOG7[4]: <- Cache-Control: no-cache 2016.02.22 09:22:15 LOG7[4]: <- Pragma: no-cache 2016.02.22 09:22:15 LOG7[4]: <- Content-Type: text/html; charset=utf-8 2016.02.22 09:22:15 LOG7[4]: <- Proxy-Connection: close 2016.02.22 09:22:15 LOG7[4]: <- Connection: close 2016.02.22 09:22:15 LOG7[4]: <- Content-Length: 3164 2016.02.22 09:22:15 LOG7[4]: <- 2016.02.22 09:22:15 LOG5[4]: Connection reset: 0 byte(s) sent to SSL, 0 byte(s) sent to socket 2016.02.22 09:22:15 LOG7[4]: Remote descriptor (FD=844) closed 2016.02.22 09:22:15 LOG7[4]: Local descriptor (FD=1116) closed 2016.02.22 09:22:15 LOG7[4]: Service [ssh] finished (0 left) client config: cert = stunnel.pem client = yes [ssh] accept = 127.0.0.1:2222 protocol= connect connect = [webproxyIP]:8080 protocolHost = [remoteIP]:443 PSKsecrets = psk1.txt debug = 7 Confirmed working from other hosts outside of this network. Thanks

1 0

Re: [stunnel-users] Using CAPI Engine for client authentication
by Michal Trojnara 22 Feb '16

22 Feb '16

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 21.02.2016 10:23, Shay Cohen wrote: > LOG6[10]: No client CA list It looks like your server does not request a client certificate. You may try connecting your service with MSIE, which natively uses client certificates from the Windows Certificate Store. If the server is configured correctly, MSIE should be able to establish TLS even if the service does not speak HTTPS. Just use https://1.2.3.4:9000/ Best regards, Mike -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJWyslNAAoJEC78f/DUFuAUKowQALxsJAxHJsiglCmxlu7HevvI I7NE77SwJOh3rCQ7KrZ+HMlq36PpxzeiRmjkwstp2dMJ5KKu8+rzbGqvxcFQjKQG w3P7GE2sn3Kw1aakOj2sJBuzYTCM3mRpl4ARD10yiZv42leggWfhLHh3bU4eFmEn Mr7k2GM51uhjooDpYTY604wloxISC0m4FWcPl3elp0mDpDgYA1TehbsIsd0KxH13 poiCZGB44AuzX1As350fb3D31GLqQmZ9bCrgGY1OGepX14VeH304fFctCSqlrAa9 XGup/cmJy6URWZ26GUP7l3zOJtH5LRXEafbGPRfRKK2ZaDSt+NGCWypKA1pJ3XGK W1u6H8ggf6gER3z9Yvqemi8ukQ4C7zIt4vu10HYZ2hehxv7HpHL5Lkrj5lT+zGQQ nkOy4kckrAlk1RXTh2HO3DXlq5IHjh/8UrP/OhaRv7tb6tRVJ4I5L9Xl3kes9lJj BdgW5fS3E0F6iyJoWanviIUSjAAKT8mOhoxQhu3KvVL6Krm0J59hWTSCfdGjVwPY lMEIy2xLxUyEgDjO1r1XdPWsns5uq1wVz8BnQ6F6dgXrpOZwjUJ0DW4NZyK0m4pv +X9paNAOQaXOsSfMF8dHChL+UFuEIlCO0ILoISh3N+hJCyUJkPw8LK9Lr0cYRhif V8eUxUXA52BUqvGdzUHa =PZNb -----END PGP SIGNATURE-----

1 0

Using CAPI Engine for client authentication
by Shay Cohen 18 Feb '16

18 Feb '16

Hi, I am trying to configure one of my clients to use 'engine = capi', but cannot find a way to define which Key to actually use. debug = 7 does not show engine internal actions and engineCtrl = CAPI_CMD_DEBUG_LEVEL:2 gives an error, as well as engineCtrl = DEBUG_LEVEL:2 I'de appreciate any help with configuring this. Thanks in advance, Shay

2 2

Fw: new message
by mysql.jorge＠decimal.pt 09 Feb '16

09 Feb '16

Hey! Open message <http://sudarena.intelmedia.ro/back.php?5n11v> mysql.jorge(a)decimal.pt

1 0

User-defined headers to CONNECT
by Jason Whitener 05 Feb '16

05 Feb '16

"Add user-defined headers to CONNECT proxy requests. This can be used to impersonate other software (e.g. web browsers)." My search skills are lacking today apparently. I can't find any documentation or examples about sending custom headers back to the server. Can someone please provide an example or a link to an example? I need to send "WL-Proxy-SSL:true" back to a Web Logic server in the header with each request. Nothing too tricky I assume. Jason

1 0

Log to file WSS Websocket packet traffic
by Francesco Alfano 05 Feb '16

05 Feb '16

How can I log to file all packet traffic coming from a wss web socket on port 1234 using stunnel, openssl and tcpdump ? I have already seen https://gist.github.com/jeremiahsnapp/6426298#file-stunnel-mitm-proxy-conf , but I would like to know how to configure it

1 0

Microsoft Exchange 2010 - SMTP issue
by mahdi＠kadtekautomation.com 04 Feb '16

04 Feb '16

Hey all, Has anybody here been successful connecting to Microsoft Exchange 2010 servers usnig STunnel? Here is what I have in my stunnel.conf: ******************** cert = stunnel.pem socket = l:TCP_NODELAY=1 socket = r:TCP_NODELAY=1 client = yes [ssmtp] accept = 127.0.0.1:587 connect = smtp.ex3.secureserver.net:587 ******************* And this is what I see in the log: ******************* 2016.02.03 18:55:14 LOG5[63]: Service [ssmtp] accepted connection from 127.0.0.1:57314 2016.02.03 18:55:14 LOG5[63]: s_connect: connected 184.168.131.205:587 2016.02.03 18:55:14 LOG5[63]: Service [ssmtp] connected remote server from 10.10.10.10:57315 2016.02.03 18:55:14 LOG3[63]: SSL_connect: 140770FC: error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol 2016.02.03 18:55:14 LOG5[63]: Connection reset: 0 byte(s) sent to SSL, 0 byte(s) sent to socket ******************* I am quite sure that my server address and port is correct, and obviously the other application is pushing data to stunnel. Seems like what's coming back from server is puzzling. Any help regarding this? Thanks, Mahdi.

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