From: Anthonin Bonnefoy <anthonin.bonne...@datadoghq.com> With EDNS, DNS packets can have a maximum size of 65507. This will allow to have a bigger accepted_payload_size which is useful when we have more than 100 SRV records. --- include/types/dns.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/include/types/dns.h b/include/types/dns.h index 488d3996..53f24c19 100644 --- a/include/types/dns.h +++ b/include/types/dns.h @@ -42,7 +42,10 @@ */ #define DNS_MAX_LABEL_SIZE 63 #define DNS_MAX_NAME_SIZE 255 -#define DNS_MAX_UDP_MESSAGE 8192 +/* With EDNS, DNS message can reach the maximum size of an UDP message + * which is (65535 - 8 bytes UDP header - 20 bytes IP header) + */ +#define DNS_MAX_UDP_MESSAGE 65507 /* DNS minimun record size: 1 char + 1 NULL + type + class */ #define DNS_MIN_RECORD_SIZE (1 + 1 + 2 + 2) -- 2.13.2
