Hide Forgot
The connect timeout is hardcoded to connect to ftp.microsoft.com on port 1234. That host:port rejects connections, the test module doesn't catch the rejection and the test fails every time. Workaround: iptables -A PREROUTING -t nat -p tcp -s 192.168.122.121 --dport 1234 -j DNAT --to 194.109.21.27:666 This causes a timeout and the test succeeds. In any case, hardcoding a competitor's systems in code that has nothing to do with them is not polite. The problem is upstream.
BTW, http://grepcode.com/file/repo1.maven.org/maven2/commons-net/commons-net/3.2/org/apache/commons/net/ftp/TestConnectTimeout.java says that it should return true on UnknownHostException. The target host sends a reset; perhaps that's not an unknown exception: 192.168.122.121.54242 > 134.170.188.232.1234: Flags [S], cksum 0x7ee3 (incorrect -> 0x5cf2), seq 3087907219, win 14600, options [mss 1460,sackOK,TS val 242866817 ecr 0,nop,wscale 7], length 0 15:51:33.935228 IP (tos 0x0, ttl 243, id 43016, offset 0, flags [DF], proto TCP (6), length 40) 134.170.188.232.1234 > 192.168.122.121.54242: Flags [R.], cksum 0xc6b0 (correct), seq 0, ack 3087907220, win 8212, length 0 Best thing might be to just disable this test.
Looks like this was fixed to use www.apache.org in 3.6, which is the only version included in RHEL8. https://github.com/apache/commons-net/commit/8fe92b712ea7e5041bbbcbfccb32d6b68d6422f6#diff-f4cc12b6f2db837728b24c9f590d3534