RFC 1785:TFTP Option Negotiation Analysis
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negotiation


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... In each case, the servers ignored the option information in the Request packet and the transfer proceeded as though no option negotiation had been attempted. In addition, the standard BSD4.3 source for TFTPD, the starting point for many implementations, was ...
... TFTP option negotiation mechanism is fully backward-compatible with unmodified TFTP ...



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