Code:
tcpdump -npi exp0 port 25
tcpdump: listening on exp0
16:20:45.715499 10.1.3.2.55548 > 74.125.22.27.25: S 2061072540:2061072540(0) win 16384 <mss 1460,nop,wscale 0,nop,nop,timestamp 14520621 0> (DF)
16:20:45.728301 74.125.22.27.25 > 10.1.3.2.55548: S 2170873922:2170873922(0) ack 2061072541 win 42540 <mss 1430,nop,nop,timestamp 2118147341 14520621,nop,wscale 7>
16:20:45.728329 10.1.3.2.55548 > 74.125.22.27.25: . ack 1 win 17160 <nop,nop,timestamp 14520621 2118147341> (DF)
16:20:45.741760 74.125.22.27.25 > 10.1.3.2.55548: P 1:54(53) ack 1 win 333 <nop,nop,timestamp 2118147354 14520621>
16:20:45.742167 10.1.3.2.55548 > 74.125.22.27.25: P 1:25(24) ack 54 win 17160 <nop,nop,timestamp 14520621 2118147354> (DF)
16:20:45.754901 74.125.22.27.25 > 10.1.3.2.55548: . ack 25 win 333 <nop,nop,timestamp 2118147367 14520621>
16:20:45.766330 74.125.22.27.25 > 10.1.3.2.55548: P 54:222(168) ack 25 win 333 <nop,nop,timestamp 2118147379 14520621>
16:20:45.768117 10.1.3.2.55548 > 74.125.22.27.25: F 25:25(0) ack 222 win 17160 <nop,nop,timestamp 14520621 2118147379> (DF)
16:20:45.769470 10.1.3.2.55549 > 64.233.186.27.25: S 2061164667:2061164667(0) win 16384 <mss 1460,nop,wscale 0,nop,nop,timestamp 14520621 0> (DF)
16:20:45.781278 74.125.22.27.25 > 10.1.3.2.55548: F 222:222(0) ack 26 win 333 <nop,nop,timestamp 2118147394 14520621>
16:20:45.781298 10.1.3.2.55548 > 74.125.22.27.25: . ack 223 win 17160 <nop,nop,timestamp 14520621 2118147394> (DF)
16:20:45.892998 64.233.186.27.25 > 10.1.3.2.55549: S 1068554356:1068554356(0) ack 2061164668 win 42540 <mss 1430,nop,nop,timestamp 2122455153 14520621,nop,wscale 7>
16:20:45.893020 10.1.3.2.55549 > 64.233.186.27.25: . ack 1 win 17160 <nop,nop,timestamp 14520621 2122455153> (DF)
16:20:46.351142 64.233.186.27.25 > 10.1.3.2.55549: P 1:53(52) ack 1 win 333 <nop,nop,timestamp 2122455612 14520621>
16:20:46.351480 10.1.3.2.55549 > 64.233.186.27.25: P 1:25(24) ack 53 win 17160 <nop,nop,timestamp 14520622 2122455612> (DF)
16:20:46.475119 64.233.186.27.25 > 10.1.3.2.55549: . ack 25 win 333 <nop,nop,timestamp 2122455735 14520622>
16:20:46.654254 64.233.186.27.25 > 10.1.3.2.55549: P 53:221(168) ack 25 win 333 <nop,nop,timestamp 2122455915 14520622>
16:20:46.655007 10.1.3.2.55549 > 64.233.186.27.25: F 25:25(0) ack 221 win 17160 <nop,nop,timestamp 14520623 2122455915> (DF)
16:20:46.656366 10.1.3.2.55550 > 64.233.186.27.25: S 2061653855:2061653855(0) win 16384 <mss 1460,nop,wscale 0,nop,nop,timestamp 14520623 0> (DF)
16:20:46.789459 64.233.186.27.25 > 10.1.3.2.55550: S 3468420545:3468420545(0) ack 2061653856 win 42540 <mss 1430,nop,nop,timestamp 2125453095 14520623,nop,wscale 7>
16:20:46.789478 10.1.3.2.55550 > 64.233.186.27.25: . ack 1 win 17160 <nop,nop,timestamp 14520623 2125453095> (DF)
16:20:46.819033 64.233.186.27.25 > 10.1.3.2.55549: . ack 26 win 333 <nop,nop,timestamp 2122456079 14520623>
16:20:46.944353 64.233.186.27.25 > 10.1.3.2.55549: F 221:221(0) ack 26 win 333 <nop,nop,timestamp 2122456205 14520623>
16:20:46.944374 10.1.3.2.55549 > 64.233.186.27.25: . ack 222 win 17160 <nop,nop,timestamp 14520624 2122456205> (DF)
16:20:47.271106 64.233.186.27.25 > 10.1.3.2.55550: P 1:54(53) ack 1 win 333 <nop,nop,timestamp 2125453577 14520623>
16:20:47.271561 10.1.3.2.55550 > 64.233.186.27.25: P 1:25(24) ack 54 win 17160 <nop,nop,timestamp 14520624 2125453577> (DF)
16:20:47.404206 64.233.186.27.25 > 10.1.3.2.55550: . ack 25 win 333 <nop,nop,timestamp 2125453710 14520624>
16:20:47.580796 64.233.186.27.25 > 10.1.3.2.55550: P 54:222(168) ack 25 win 333 <nop,nop,timestamp 2125453887 14520624>
16:20:47.581449 10.1.3.2.55550 > 64.233.186.27.25: F 25:25(0) ack 222 win 17160 <nop,nop,timestamp 14520625 2125453887> (DF)
16:20:47.754376 64.233.186.27.25 > 10.1.3.2.55550: . ack 26 win 333 <nop,nop,timestamp 2125454060 14520625>
16:20:47.887736 64.233.186.27.25 > 10.1.3.2.55550: F 222:222(0) ack 26 win 333 <nop,nop,timestamp 2125454194 14520625>
16:20:47.887751 10.1.3.2.55550 > 64.233.186.27.25: . ack 223 win 17160 <nop,nop,timestamp 14520625 2125454194> (DF)