Clients from a specific WAN network can't access application layer

Help!
3

Thank you very much lukastribus!

Sadly I have poor network debuging skills… I try to tcpdump it and this is what I get when I try to access the haproxy stats page:

[root@myhaproxy ~]# tcpdump port 9000 -i ens192
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on ens192, link-type EN10MB (Ethernet), capture size 262144 bytes
13:39:08.674573 IP 192.168.2.10.49510 > myhaproxy.cslistener: Flags [S], seq 4010027171, win 65535, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
13:39:08.674625 IP myhaproxy.cslistener > 192.168.2.10.49510: Flags [S.], seq 2138253499, ack 4010027172, win 29200, options [mss 1460,nop,nop,sackOK,nop,wscale 7], length 0
13:39:08.675026 IP 192.168.2.10.49511 > myhaproxy.cslistener: Flags [S], seq 3904051396, win 65535, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
13:39:08.675059 IP myhaproxy.cslistener > 192.168.2.10.49511: Flags [S.], seq 2279332806, ack 3904051397, win 29200, options [mss 1460,nop,nop,sackOK,nop,wscale 7], length 0
13:39:08.703168 IP 192.168.2.10.49510 > myhaproxy.cslistener: Flags [.], ack 1, win 1024, length 0
13:39:08.705298 IP 192.168.2.10.49510 > myhaproxy.cslistener: Flags [P.], seq 1:348, ack 1, win 1024, length 347
13:39:08.705485 IP myhaproxy.cslistener > 192.168.2.10.49510: Flags [.], seq 1:2921, ack 348, win 237, length 2920
13:39:08.705507 IP myhaproxy.cslistener > 192.168.2.10.49510: Flags [.], seq 2921:5841, ack 348, win 237, length 2920
13:39:08.705538 IP myhaproxy.cslistener > 192.168.2.10.49510: Flags [.], seq 5841:7301, ack 348, win 237, length 1460
13:39:08.705569 IP myhaproxy.cslistener > 192.168.2.10.49510: Flags [.], seq 7301:7342, ack 348, win 237, length 41
13:39:08.705629 IP myhaproxy.cslistener > 192.168.2.10.49510: Flags [.], seq 7342:10262, ack 348, win 237, length 2920
13:39:08.705644 IP myhaproxy.cslistener > 192.168.2.10.49510: Flags [.], seq 10262:13182, ack 348, win 237, length 2920
13:39:08.705708 IP 192.168.2.10.49511 > myhaproxy.cslistener: Flags [.], ack 1, win 1024, length 0
13:39:08.726801 IP 192.168.2.10.49510 > myhaproxy.cslistener: Flags [.], ack 1, win 1024, options [nop,nop,sack 1 {7301:7342}], length 0
13:39:08.726828 IP myhaproxy.cslistener > 192.168.2.10.49510: Flags [.], seq 1:1461, ack 348, win 237, length 1460
13:39:08.954969 IP myhaproxy.cslistener > 192.168.2.10.49510: Flags [.], seq 1:1461, ack 348, win 237, length 1460
13:39:09.414038 IP myhaproxy.cslistener > 192.168.2.10.49510: Flags [.], seq 1:1461, ack 348, win 237, length 1460
13:39:10.333003 IP myhaproxy.cslistener > 192.168.2.10.49510: Flags [.], seq 1:1461, ack 348, win 237, length 1460
13:39:12.169012 IP myhaproxy.cslistener > 192.168.2.10.49510: Flags [.], seq 1:1461, ack 348, win 237, length 1460
13:39:15.844997 IP myhaproxy.cslistener > 192.168.2.10.49510: Flags [.], seq 1:1461, ack 348, win 237, length 1460
13:39:18.705153 IP myhaproxy.cslistener > 192.168.2.10.49511: Flags [F.], seq 1:213, ack 1, win 229, length 212
13:39:18.725324 IP 192.168.2.10.49511 > myhaproxy.cslistener: Flags [.], ack 214, win 1023, length 0
13:39:23.189049 IP myhaproxy.cslistener > 192.168.2.10.49510: Flags [.], seq 1:1461, ack 348, win 237, length 1460
13:39:37.876995 IP myhaproxy.cslistener > 192.168.2.10.49510: Flags [.], seq 1:1461, ack 348, win 237, length 1460
13:40:07.220992 IP myhaproxy.cslistener > 192.168.2.10.49510: Flags [.], seq 1:1461, ack 348, win 237, length 1460

Regards