When I do a request to a nameserver which has dnssec the response is sometimes incomplete
i looked around on the web and found some information regarding the issue
2.3.4 Size limits
https://www.rfc-editor.org/rfc/rfc1035
It saysUDP messages 512 octets or less
To receive a bigger response I need EDNS0 so i can receive a max of 4096 bytes.I can't really figure out how to use/enable EDNS0
EDNS0 info:
https://www.rfc-editor.org/rfc/rfc2671
EDIT
i have to send an OPT RR with my request to get more data back. i have an example from microsoft, but they use a type RRSIG. i want to use a type ANY.
http://img266.imageshack.us/img266/6707/optf.png
The question:
can someone explain how EDNS0 works and why my opt rr is not working.(i use the same as the microsoft example)
thx in advance:)
For some odd reason my request is working now.
Request i send:
01 01 01 00 00 01 00 00 00 00 00 01". domain2dns($domainname) ."00 00 ff 00 01 00 00 29 10 00 00 00 00 00 00 00
explanation of the EDNS part
Name: 00
Type: 00 29
UDP Payload size: 10 00
Higher bits in extended RCODE:00
EDNS0 version: 00
Z: 00 00
Data Lenght: 00 00
NAME - - domain name -- empty (root domain)
TYPE - - u_int16_t ---- OPT
CLASS - u_int16_t ---- sender's UDP payload size
TTL - - - u_int32_t ---- extended RCODE and flags
RDLEN - u_int16_t ---- describes RDATA
RDATA - octet stream - {attribute,value} pairs
Problem solved
thx guys :)
