On Sat, Jul 23, 2016 at 11:07 AM, Jimmy Hess <mysidia@gmail.com> wrote:
In addition, the string component of each DNS label is limited to 63 octets.
This is a hard limit in the DNS packet format. In the packet, the dots are replaced by either: 1 byte whose high two bits are 0 and whose low six bits are the length of the next label, 0 to 63. 0 means done, end of the name. 2 bytes, whose high two bits are 1 and whose low 14 bits are the byte offset within the DNS packet where the name continues So what happens is: if there are three names in the DNS packet: www.example.com, ns1.example.com, and ns2.example.com, then the packet will store www.example.com in full (with the dots replaced with the next label length) and then it'll store ns1 followed by a pointer to where "example.com" began in www.example.com and finally it'll store ns2 followed by a pointer to where "example.com" began in www.example.com. Regards, Bill Herrin -- William Herrin ................ herrin@dirtside.com bill@herrin.us Owner, Dirtside Systems ......... Web: <http://www.dirtside.com/>