cannot ssh into a box with DHCP assigned IP address

[Anton Shterenlikht]

	From ml at my.gd Wed Feb 20 10:11:12 2013

	Run this on your server:

	tcpdump -ni wlan0 ip and port 22

	Then try to ssh to the box,
	 see if SYN packets arrive,
	 see if your box sends SYN/ACK back.

172.21.220.12 is the ssh server
137.222.187.241 is the ssh client (where I login from)

There's lots of output on the server:

10:13:40.396933 IP 172.21.220.12.20541 > 137.222.187.241.22: Flags [P.], seq 528
:576, ack 897, win 1040, options [nop,nop,TS val 166697722 ecr 2764601194], leng
th 48
10:13:40.400142 IP 137.222.187.241.22 > 172.21.220.12.20541: Flags [P.], seq 897
:945, ack 576, win 1040, options [nop,nop,TS val 2764601829 ecr 166697722], leng
th 48
10:13:40.499768 IP 172.21.220.12.20541 > 137.222.187.241.22: Flags [.], ack 945,
 win 1040, options [nop,nop,TS val 166697825 ecr 2764601829], length 0
10:13:41.126804 IP 172.21.220.12.20541 > 137.222.187.241.22: Flags [P.], seq 576
:624, ack 945, win 1040, options [nop,nop,TS val 166698452 ecr 2764601829], leng
th 48
10:13:41.129465 IP 137.222.187.241.22 > 172.21.220.12.20541: Flags [P.], seq 945
:993, ack 624, win 1040, options [nop,nop,TS val 2764602558 ecr 166698452], leng
th 48
10:13:41.229792 IP 172.21.220.12.20541 > 137.222.187.241.22: Flags [.], ack 993,
 win 1040, options [nop,nop,TS val 166698555 ecr 2764602558], length 0
10:14:06.042148 IP 137.222.187.241.22 > 172.21.220.12.46009: Flags [P.], seq 691
166491:691166555, ack 2147595671, win 1040, options [nop,nop,TS val 2121228740 e
cr 166423364], length 64
10:14:06.043854 IP 172.21.220.12.46009 > 137.222.187.241.22: Flags [P.], seq 1:3
3, ack 64, win 1040, options [nop,nop,TS val 166723368 ecr 2121228740], length 3
2
10:14:06.144924 IP 137.222.187.241.22 > 172.21.220.12.46009: Flags [.], ack 33,
win 1040, options [nop,nop,TS val 2121228843 ecr 166723368], length 0

10:15:02.017361 IP 137.222.187.241.22 > 172.21.220.12.46009: Flags [P.], seq 159
04:16240, ack 7169, win 1040, options [nop,nop,TS val 2121284715 ecr 166779337],
 length 336
10:15:02.017969 IP 137.222.187.241.22 > 172.21.220.12.46009: Flags [P.], seq 162
40:16576, ack 7169, win 1040, options [nop,nop,TS val 2121284716 ecr 166779337],
 length 336
10:15:02.018079 IP 172.21.220.12.46009 > 137.222.187.241.22: Flags [.], ack 1657
6, win 1035, options [nop,nop,TS val 166779343 ecr 2121284715], length 0
10:15:02.018319 IP 137.222.187.241.22 > 172.21.220.12.46009: Flags [P.], seq 165
76:16896, ack 7169, win 1040, options [nop,nop,TS val 2121284716 ecr 166779337],
 length 320
10:15:02.018510 IP 137.222.187.241.22 > 172.21.220.12.46009: Flags [P.], seq 168
96:17232, ack 7169, win 1040, options [nop,nop,TS val 2121284716 ecr 166779337],
 length 336
10:15:02.018626 IP 172.21.220.12.46009 > 137.222.187.241.22: Flags [.], ack 1723
2, win 1030, options [nop,nop,TS val 166779344 ecr 2121284716], length 0
10:15:02.019583 IP 137.222.187.241.22 > 172.21.220.12.46009: Flags [P.], seq 172
32:17568, ack 7169, win 1040, options [nop,nop,TS val 2121284716 ecr 166779337],
 length 336
10:15:02.019840 IP 137.222.187.241.22 > 172.21.220.12.46009: Flags [P.], seq 175
68:17840, ack 7169, win 1040, options [nop,nop,TS val 2121284717 ecr 166779337],
 length 272
10:15:02.019927 IP 172.21.220.12.46009 > 137.222.187.241.22: Flags [.], ack 1784
0, win 1036, options [nop,nop,TS val 166779345 ecr 2121284716], length 0

Thanks

Anton