I feel that there might be an issue with the Linux RemoteRS application now. I just tried to use ExpertSDR2 Remote Client and that also cannot communicate with the RemoteRS application on port 5050.
Here is the packet capture for that communications. In this 10.10.10.88 is the workstation and again 10.10.10.74 is the server:
root@station:~# tcpdump -nni any -vvXs0 port 5050
tcpdump: listening on any, link-type LINUX_SLL (Linux cooked), capture size 262144 bytes
11:56:10.173007 IP (tos 0x0, ttl 128, id 12891, offset 0, flags [DF], proto TCP (6), length 40)
10.10.10.88.60137 > 10.10.10.74.5050: Flags [R.], cksum 0x2202 (correct), seq 1148731536, ack 1234278363, win 0, length 0
0x0000: 4500 0028 325b 4000 8006 9fbf 0a0a 0a58 E..(2[@........X
0x0010: 0a0a 0a4a eae9 13ba 4478 4090 4991 97db ...J....Dx@.I...
0x0020: 5014 0000 2202 0000 0000 0000 0000 P...".........
11:56:24.429053 IP (tos 0x0, ttl 128, id 12892, offset 0, flags [DF], proto TCP (6), length 52)
10.10.10.88.60148 > 10.10.10.74.5050: Flags [S], cksum 0xd08c (correct), seq 2537612525, win 64240, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
0x0000: 4500 0034 325c 4000 8006 9fb2 0a0a 0a58 E..42\@........X
0x0010: 0a0a 0a4a eaf4 13ba 9740 e4ed 0000 0000 ...J.....@......
0x0020: 8002 faf0 d08c 0000 0204 05b4 0103 0308 ................
0x0030: 0101 0402 ....
11:56:24.429088 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 52)
10.10.10.74.5050 > 10.10.10.88.60148: Flags [S.], cksum 0x28dc (incorrect -> 0xa459), seq 329586811, ack 2537612526, win 64240, options [mss 1460,nop,nop,sackOK,nop,wscale 10], length 0
0x0000: 4500 0034 0000 4000 4006 120f 0a0a 0a4a E..4..@.@......J
0x0010: 0a0a 0a58 13ba eaf4 13a5 187b 9740 e4ee ...X.......{.@..
0x0020: 8012 faf0 28dc 0000 0204 05b4 0101 0402 ....(...........
0x0030: 0103 030a ....
11:56:24.429501 IP (tos 0x0, ttl 128, id 12893, offset 0, flags [DF], proto TCP (6), length 40)
10.10.10.88.60148 > 10.10.10.74.5050: Flags [.], cksum 0xc00b (correct), seq 1, ack 1, win 8212, length 0
0x0000: 4500 0028 325d 4000 8006 9fbd 0a0a 0a58 E..(2]@........X
0x0010: 0a0a 0a4a eaf4 13ba 9740 e4ee 13a5 187c ...J.....@.....|
0x0020: 5010 2014 c00b 0000 0000 0000 0000 P.............
11:56:24.431921 IP (tos 0x0, ttl 128, id 12894, offset 0, flags [DF], proto TCP (6), length 195)
10.10.10.88.60148 > 10.10.10.74.5050: Flags [P.], cksum 0xf5c0 (correct), seq 1:156, ack 1, win 8212, length 155
0x0000: 4500 00c3 325e 4000 8006 9f21 0a0a 0a58 E...2^@....!...X
0x0010: 0a0a 0a4a eaf4 13ba 9740 e4ee 13a5 187c ...J.....@.....|
0x0020: 5018 2014 f5c0 0000 4745 5420 2f20 4854 P.......GET./.HT
0x0030: 5450 2f31 2e31 0d0a 486f 7374 3a20 3130 TP/1.1..Host:.10
0x0040: 2e31 302e 3130 2e37 343a 3530 3530 0d0a .10.10.74:5050..
0x0050: 5570 6772 6164 653a 2077 6562 736f 636b Upgrade:.websock
0x0060: 6574 0d0a 436f 6e6e 6563 7469 6f6e 3a20 et..Connection:.
0x0070: 5570 6772 6164 650d 0a53 6563 2d57 6562 Upgrade..Sec-Web
0x0080: 536f 636b 6574 2d4b 6579 3a20 556e 6330 Socket-Key:.Unc0
0x0090: 7a78 5a51 3971 366b 3277 2f50 6863 614d zxZQ9q6k2w/PhcaM
0x00a0: 3677 3d3d 0d0a 5365 632d 5765 6253 6f63 6w==..Sec-WebSoc
0x00b0: 6b65 742d 5665 7273 696f 6e3a 2031 330d ket-Version:.13.
0x00c0: 0a0d 0a ...
11:56:24.431939 IP (tos 0x0, ttl 64, id 61541, offset 0, flags [DF], proto TCP (6), length 40)
10.10.10.74.5050 > 10.10.10.88.60148: Flags [.], cksum 0x28d0 (incorrect -> 0xdf45), seq 1, ack 156, win 63, length 0
0x0000: 4500 0028 f065 4000 4006 21b5 0a0a 0a4a E..(.e@.@.!....J
0x0010: 0a0a 0a58 13ba eaf4 13a5 187c 9740 e589 ...X.......|.@..
0x0020: 5010 003f 28d0 0000 P..?(...