Question:

I am dev'n an application to work with DCC Resume. I send the resume command, recive the accept command, and connect to the port to start the transfer. As soon as this occurs mIRC stops the transfer. Does the sent checksum process change with a Resume? Or is there something else I am missing? Thank You

Do u already have it working with dcc send?

I remeber someone else had some trouble with not using bigend values (most significant byte first) in the checksum, maybe yours is the same problem, I gave up on mine, i just found it to time consuming to script into a mirc a replacement resume, but im assuming your doing this in another language.

PS: if im all to hell with what im saying, sorry its getting late and the mind drifts

Yeah I use the same standard function for the normal DCC Send connection, only my position in the file of course is from the end, and I connect after receiving the ACCEPT. The DCC Send socket works terrific for a normal send, however when you call it after a resume, it accepts once, receivs data, sends check again, and mIRC terminates the connection. This is all done in Borland Delphi.

This is from my file on it
DCC FILE
Data is sent in packets, rather than dumped in a stream manner.
This allows the DCC SEND connection to survive where an FTP
connection might fail. The size of the packets is up to the
client, and may be set by the user. Smaller packets result
in a higher probability of survival over bad links.
The recipient should acknowledge each packet by transmitting
the total number of bytes received as an unsigned, 4 byte
integer in network byte order. The sender should not continue
to transmit until the recipient has acknowledged all data
already transmitted. Additionally, the sender should not
close the connection until the last byte has been
acknowledged by the recipient.

Are you transmitting the bytes recieved in the transfer or the total bytes recieved for the file (ie resumed at 1,000,000 and just got 8,192 so its 1,008,192) ?
I dont know which one is correct but which ever your using I suggest you try the other one. ;-)

Thank you for your input, it has been most helpful in me correcting everything with my program, which now works terrifcly. Thanks once again.