On 9.6.2012, at 4.55, Matthias-Christian Ott wrote: > Yes, there is. You have to replicate the entire state of the IMAP > session (protocol states, buffers, TLS state etc.) and the TCP state of > the connection. The state of the IMAP session is (in theory) easily > replicable (although you probably have to rely on internals of the TLS > implementation; OpenSSL can serialise TLS sessions from/into ASN.1 via > i2d_SSL_SESSION, though this is meant to resume session via TLS)
Interesting! I thought OpenSSL didn't have a way to [de]serialize the session state. The first time I wanted to do that was 13 years ago. I see there are some google hits for i2d_SSL_SESSION, but do you already know a good web page / example code I could look at? > and for > TCP there is RTCP [1]. RTCP intercepts the TCP session is able to > recover the TCP state. It works without any modification of the > operating system (at the moment limited to Linux). Thanks for this too. > If this would be implemented in Dovecot it would really set it apart > from other IMAP servers and software that I've seen so far. Being able > to transparently handle failover of a TCP connection is unique. Yes.