>From the servers perspective:

Receives StartupPacket

|

|

(Is SSL_NEGOTIATE_CODE?) ----------- Normal startup

| No

|

| Yes

|

|

(Server compiled with USE_SSL?) ------- Send 'N'

| No |

| |

| Yes Normal startup

|

|

Send 'S'

|

|

Establish SSL

|

|

Normal startup

>From the clients perspective (v6.6 client _with_ SSL):

Connect

|

|

Send packet with SSL_NEGOTIATE_CODE

|

|

Receive single char ------- 'S' -------- Establish SSL

| |

| '<else>' |

| Normal startup

|

|

Is it 'E' for error ------------------- Retry connection

| Yes without SSL

| No

|

Is it 'N' for normal ------------------- Normal startup

| Yes

|

Fail with unknown