On Tue, Oct 31, 2023 at 1:28 PM Luis Carlos Chalaca Figueira via curl-library <curl-library@lists.haxx.se> wrote: > > I'm building a web crawler. > > Started with python but the need for speed led me to libcurl. > > The obstacle I'm having is: when using the multi interface a big part of > the the connections cloe because of the error "Could not resolve host:" > > What I've tried: > > 1 - Confirmed that all URLs are correct. > > 2 - Confirmed that using the easy interface URLs are resolved. > > 3 - Confirmed that other programs like dig, resolvectl, nslookup can > resolve URLs that multi interface couldn't. > > 4 - Set a "reputable" DNS server doing: curl_easy_setopt(handles[i], > CURLOPT_DNS_SERVERS, "8.8.8.8");. > > 5 - In the file /etc/nsswitch.conf, line "hosts: files > nDNS[NOTFOUNDED=return] dns" I deleted [NOTFOUNDED=return]. > > 6 - I've turned verbose on - Doesn't help me much. > > I don't know what to do more as it seems a problem inside the library, > so i posted here before going digging in the library.
I _think_ step (5) - modification of /etc/nsswitch.conf - may be the problem. I seem to recall '[NOTFOUNDED=return]' is needed to ensure the next provider is tried. Without it, weird things happen. I don't have much experience with fiddling with nsswitch.conf. But I vaguely recall reading about it several times. And as Dmitry said, Wireshark may be a good idea. That should tell you if nss is making the DNS query. It may show only the mDNS query is happening. Jeff -- Unsubscribe: https://lists.haxx.se/mailman/listinfo/curl-library Etiquette: https://curl.se/mail/etiquette.html
