tnw07b is responding to pings but ssh connections are reset. Oops, I made a mistake, nmap does look like a DSM. (Port 22 is ssh, 8888 is tinyproxy, 30000 is dsm. Xinetd check-mk 6556 is not listed I suspect because nmap does not scan it by default.)
[daq@ustar raw_data]$ nmap tnw07b
Starting Nmap 7.40 ( https://nmap.org ) at 2017-03-10 17:40 WET
Nmap scan report for tnw07b (192.168.1.146)
Host is up (0.055s latency).
Not shown: 997 closed ports
PORT STATE SERVICE
22/tcp open ssh
8888/tcp open sun-answerbook
30000/tcp open ndmps
And data are coming in:
tnw07b:/dev/gps_pty0 7 2 32 2017 03 10 17:41:25.874 03 10 17:41:41.036 2.04 0.142 0.925 69 80
tnw07b:/dev/ttyUSB0 7 22 16 2017 03 10 17:41:25.828 03 10 17:41:40.958 0.99 1.008 1.009 39 39
tnw07b:/dev/ttyUSB4 7 102 16 2017 03 10 17:41:26.368 03 10 17:41:41.434 1.00 1.004 1.005 38 38
tnw07b:/dev/ttyUSB7 7 32768 4 2017 03 10 17:41:26.049 03 10 17:41:41.049 0.20 4.772 5.228 17 30
The data connection to dsm_server is in fact from the right IP address, so tnw07b appears to be configured correctly:
[root@ustar daq]# netstat -ap | grep tnw07b
tcp 0 0 ustar:51968 tnw07b:43666 ESTABLISHED 9440/dsm_server
According to nagios, tnw07b was responding to check-mk requests until 2017-03-09 10:52 UTC, so something happened then which now causes network connections to be reset. Probably this system needs to be rebooted.