Client should terminate ID string sent during protocol version exchange with CR LF (carriage return, line feed) rather than only LF, as is done in the current version. RFC 2453 (http://tools.ietf.org/html/rfc4253#section-4.2) suggests that CR LF should be used to terminate the sent line while either CR LF or just LF may be expected in a received ID string (for compatibility with older protocol versions).
Created attachment 1523 [details] Send and receive proto banners with CR LF for proto 2 This patch changes the banner to use CR LF when running as a pure protocol 2 server (which is the default for new installs these days) and in the client when it's talking to a server with protocol 2 (regardless of whether or not the server advertises 1.99 or 2.0). It doesn't change the behaviour when acting as a protocol 1.5 or 1.99 server, or as a 1.5 client. This will need serious interop testing, though.
Thanks for the report. The patch has been applied and this change will be in the 5.1 release.
Mass update RESOLVED->CLOSED after release of openssh-5.1