In message <001501ca5785$257c7220$21011...@china.huawei.com>, Ashwin writes: > > Hi All, > > RFC 2671 mentions in Section 5.3 > > Responders who do not understand these protocol extensions are > expected to send a response with RCODE NOTIMPL, FORMERR, or > SERVFAIL. > > However the above mentioned error codes are shared [SERVFAIL, NOTIMPL] are > shared, so how do we ascertain that the error code returned is an indication > that a particular server is non-EDNS, since the error might be returned due > to some other reason also. > > So essentially my query is how do we decide that a particular server is EDNS > or not? Can it be assumed that each time the above three error codes are > returned , it signifies that the DNS server is not EDNS capable?
You assume it is EDNS if it is in response to a EDNS query and retry w/o EDNS. It the problem is EDNS the plain DNS query will succeed. If it is not EDNS the plain EDNS query will fail. > Regards > > Ashwin -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org _______________________________________________ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
