Sometimes you see this message in Nmap output:

Warning: xxx.xxx.xxx.xxx giving up on port because retransmission cap hit (10).

It would be nice to add the port number here as well, in case you want to manually investigate that host and port after the scan has finished.

Something like:

Warning: xxx.xxx.xxx.xxx giving up on port 12345/tcp because retransmission cap hit (10).
``

You can sniff a packet, modify it, and re-send it using libtins. The only issue is dropping the original one so the receiver doesn't get two packets. This could be done via iptables rules, I'm sure there has to be some article describing how to do it.

Originally posted by @mfontanini in mfontanini/libtins#61 (comment)

The pcap-filter man page could benefit from some clarifications and improvements, such as:

1. proto qualifiers: The man page reads, "proto qualifiers restrict the match to a particular protocol. Possible protos are: ether, fddi, tr, wlan, ip, ip6, arp, rarp, decnet, tcp and udp. " However, as noted in the discussion from http://ask.wireshark.org/questions/26350/how-to-filter-wlan-with-a-capture

Because value type is (signed) Short
tcp/udp port is unsigned 16bit number but java's Short can't handle it.
As a result, some operation like compareTo() doesn't work.