Hi, I'm currently developing an email client that connects to POP3 server (MS Exchange) via an ISA server. I am experiencing POP Buffer Overflow problems. The POP mailbox I am connecting too contains several hundred messages and I am attemping to send "LIST x" where x is the message number i.e. in a loop from 1 to total_number_of_messages. The error ALWAYS occurs after my client has sent 4096 bytes i.e. this is the TOTAL number of bytes sent after the socket has connected. I am _not_ overflowing a buffer - at least not intentionally. Any ideas? Paul