tailhook/dns-parser

Got ReservedBitsAreNonZero errors

Closed this issue · 3 comments

lilydjwg commented

My dig command generates DNS packets that has the AD bit set (the 11th bit in flags) as Wireshark shows to me. But dns-parser thinks that bit should be zero because it's reserved.

I think reserved data should be stored as-is, without checked, as it may have meaning in the future.

tailhook commented

Here is the citation:

Z Reserved for future use. Must be zero in all queries
and responses.

As I understand the text if a bit is set the request may be a different thing at all. Like a domain name is in a different encoding or something. All of that may have security implications.

Anyway, what is "AD" bit (any link)? If it's something that is widely used let's just implement it.

lilydjwg commented

Here's it: https://www.ietf.org/rfc/rfc3655.txt.

Wireshark also shows "Non-authenticated data: Unacceptable" for the next bit (set as 0 by dig), but I didn't find any link explaining what it is.

tailhook commented

Hm, it looks like we need to expose that bit as a boolean flag, but can otherwise ignore it. Do you want to make a pull request?