[...] > Presumably, if pcap_compile_ex() or pcap_compile_nonameres() or whatever > were to disable name resolution, it would treat *all* host names as failing > to resolve, so > > host www.example.com > > would fail to compile. This means, of course, that the pre-test would > always fail unless you use IP addresses instead of host names. > > Wireshark's capture filter text box checks the syntax of the filter, showing > a red background if it doesn't compile and a green background if it does; it > runs the check in a separate thread and, until the thread completes doing > the name resolution, the background is yellow, meaning "I don't know yet > whether this is valid".
Well, yes, but something else applies even without a separate function to avoid the timeout. As far as I understand in this case, if one really must use hostnames in the filter expression (for instance, if the A/AAAA addresses change often or when there are multiple software instances and each of them gets a different response from the resolver), pre-testing without DNS is simply impossible. If it is more important to be able to pre-test without DNS, the filter must be changed to use no hostnames. -- Denis Ovsienko _______________________________________________ tcpdump-workers mailing list tcpdump-workers@lists.tcpdump.org https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers