Seems that when communicating my jails aren't answering back:
tcpdump:
00:00:00.000000 70:be:9b:50:dd:10 > 1c:cc:f7:e3:46:59, ethertype IPv4 (0x0800), length 74: xxx.24.140.160.49571 > xx.120.81.4.22: Flags [S], seq 2168901959, win 14600, options [mss 1460,sackOK,TS val 1153703 ecr...