diff options
| -rw-r--r-- | src/resolve/resolved-dns-server.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/src/resolve/resolved-dns-server.c b/src/resolve/resolved-dns-server.c index 0de6c8cec0..1600e7c292 100644 --- a/src/resolve/resolved-dns-server.c +++ b/src/resolve/resolved-dns-server.c @@ -277,6 +277,14 @@ void dns_server_packet_failed(DnsServer *s, DnsServerFeatureLevel level) { if (s->possible_feature_level != level) return; + /* Invoked whenever we get a FORMERR, SERVFAIL or NOTIMP rcode from a server. This is an immediate trigger for + * us to go one feature level down. Except when we are already at TCP or UDP level, in which case there's no + * point in changing, under the assumption that packet failures are caused by packet contents, not by used + * transport. */ + + if (s->possible_feature_level <= DNS_SERVER_FEATURE_LEVEL_UDP) + return; + s->n_failed_attempts = (unsigned) -1; } |