Follow up on FreeBSD's traffic and syndrome looks like :


With stunnel's transparent set option traffic looks like :

19:31:34.162337 IP 192.168.103.69.52671 > 127.0.0.1.80: Flags [S], seq
2050938762, win 65535, options [mss 16344,nop,wscale 3,sackOK,TS val
7437993 ecr 0], length 0
19:31:37.153079 IP 192.168.103.69.52671 > 127.0.0.1.80: Flags [S], <snip>..
19:31:40.351804 IP 192.168.103.69.52671 > 127.0.0.1.80: Flags [S], <snip> ..
19:31:43.550543 IP 192.168.103.69.52671 > 127.0.0.1.80: Flags [S], seq
2050938762, win 65535, options [mss 16344,sackOK,eol], length 0

...

2011.01.07 19:32:55 LOG7[6662:34378629568]: Service ssh_proxy accepted FD=13 from 192.168.103.69:52673
2011.01.07 19:32:55 LOG7[6662:34379125184]: Service ssh_proxy started
2011.01.07 19:32:55 LOG7[6662:34379125184]: FD=13 in non-blocking mode
2011.01.07 19:32:55 LOG7[6662:34379125184]: Option TCP_NODELAY set on local socket
2011.01.07 19:32:55 LOG7[6662:34379125184]: Waiting for a libwrap process
2011.01.07 19:32:55 LOG7[6662:34379125184]: Acquired libwrap process #0
2011.01.07 19:32:55 LOG7[6662:34379125184]: Releasing libwrap process #0
2011.01.07 19:32:55 LOG7[6662:34379125184]: Released libwrap process #0
2011.01.07 19:32:55 LOG7[6662:34379125184]: Service ssh_proxy permitted by libwrap from 192.168.103.69:52673
2011.01.07 19:32:55 LOG5[6662:34379125184]: Service ssh_proxy accepted connection from 192.168.103.69:52673
2011.01.07 19:32:55 LOG7[6662:34379125184]: SSL state (accept): before/accept initialization
2011.01.07 19:32:55 LOG7[6662:34379125184]: SSL state (accept): SSLv3 read client hello A
2011.01.07 19:32:55 LOG7[6662:34379125184]: SSL state (accept): SSLv3 write server hello A
2011.01.07 19:32:55 LOG7[6662:34379125184]: SSL state (accept): SSLv3 write certificate A
2011.01.07 19:32:55 LOG7[6662:34379125184]: SSL state (accept): SSLv3 write server done A
2011.01.07 19:32:55 LOG7[6662:34379125184]: SSL state (accept): SSLv3 flush data
2011.01.07 19:32:55 LOG7[6662:34379125184]: SSL state (accept): SSLv3 read client key exchange A
2011.01.07 19:32:55 LOG7[6662:34379125184]: SSL state (accept): SSLv3 read finished A
2011.01.07 19:32:55 LOG7[6662:34379125184]: SSL state (accept): SSLv3 write change cipher spec A
2011.01.07 19:32:55 LOG7[6662:34379125184]: SSL state (accept): SSLv3 write finished A
2011.01.07 19:32:55 LOG7[6662:34379125184]: SSL state (accept): SSLv3 flush data
2011.01.07 19:32:55 LOG7[6662:34379125184]:    1 items in the session cache
2011.01.07 19:32:55 LOG7[6662:34379125184]:    0 client connects (SSL_connect())
2011.01.07 19:32:55 LOG7[6662:34379125184]:    0 client connects that finished
2011.01.07 19:32:55 LOG7[6662:34379125184]:    0 client renegotiations requested
2011.01.07 19:32:55 LOG7[6662:34379125184]:    1 server connects (SSL_accept())
2011.01.07 19:32:55 LOG7[6662:34379125184]:    1 server connects that finished
2011.01.07 19:32:55 LOG7[6662:34379125184]:    0 server renegotiations requested
2011.01.07 19:32:55 LOG7[6662:34379125184]:    0 session cache hits
2011.01.07 19:32:55 LOG7[6662:34379125184]:    0 external session cache hits
2011.01.07 19:32:55 LOG7[6662:34379125184]:    0 session cache misses
2011.01.07 19:32:55 LOG7[6662:34379125184]:    0 session cache timeouts
2011.01.07 19:32:55 LOG6[6662:34379125184]: SSL accepted: new session negotiated
2011.01.07 19:32:55 LOG6[6662:34379125184]: Negotiated ciphers: AES256-SHA SSLv3 Kx=RSA Au=RSA Enc=AES(256) Mac=SHA1
2011.01.07 19:32:55 LOG7[6662:34379125184]: FD=14 in non-blocking mode
2011.01.07 19:32:55 LOG6[6662:34379125184]: connect_blocking: connecting 127.0.0.1:80
2011.01.07 19:32:55 LOG5[6662:34379125184]: connect_blocking: connected 127.0.0.1:80
2011.01.07 19:32:55 LOG5[6662:34379125184]: Service ssh_proxy connected remote server from 127.0.0.1:30326
2011.01.07 19:32:55 LOG7[6662:34379125184]: Remote FD=14 initialized
2011.01.07 19:32:55 LOG7[6662:34379125184]: Option TCP_NODELAY set on remote socket
2011.01.07 19:32:58 LOG7[6662:34379125184]: SSL socket closed on SSL_read
2011.01.07 19:32:58 LOG7[6662:34379125184]: Socket write shutdown
2011.01.07 19:32:58 LOG5[6662:34379125184]: Connection closed: 0 bytes sent to SSL, 0 bytes sent to socket
2011.01.07 19:32:58 LOG7[6662:34379125184]: Service ssh_proxy finished (0 left)

Without transparent, traffic flows fine, and looks like :

19:32:55.883404 IP 127.0.0.1.30326 > 127.0.0.1.80: Flags [S], seq
2147354729, win 65535, options [mss 16344,nop,wscale 3,sackOK,TS val
7446169 ecr 0], length 0
19:32:55.883575 IP 127.0.0.1.80 > 127.0.0.1.30326: Flags [S.], seq
2770470513, ack 2147354730, win 65535, options [mss 16344,nop,wscale
3,sackOK,TS val 1229815108 ecr 7446169], length 0
19:32:55.883589 IP 127.0.0.1.30326 > 127.0.0.1.80: Flags [.], ack 1, win
8960, options [nop,nop,TS val 7446169 ecr 1229815108], length 0