Hello,
I have tried your scenario, but the issue seems specific to your set up. as I was assigned with the IP from RUT240 DHCP. Looking at the RUT240 logs, after the completion of initialization sequence, DHCP exchange occurs immediately:
Fri Nov 18 18:04:47 2022 daemon.notice openvpn(Server)[7022]: Peer Connection Initiated with [AF_INET]88.119.158.92:59175
Fri Nov 18 18:04:48 2022 daemon.warn openvpn(Server)[7022]: WARNING: this configuration may cache passwords in memory -- use the auth-nocache option to prevent this
Fri Nov 18 18:04:48 2022 daemon.notice openvpn(Server)[7022]: Initialization Sequence Completed
Fri Nov 18 18:04:50 2022 daemon.info dnsmasq-dhcp[3551]: DHCPDISCOVER(br-lan) 00:ff:48:b5:1c:e3
Fri Nov 18 18:04:50 2022 daemon.info dnsmasq-dhcp[3551]: DHCPOFFER(br-lan) 192.168.5.151 00:ff:48:b5:1c:e3
Fri Nov 18 18:04:50 2022 daemon.info dnsmasq-dhcp[3551]: DHCPREQUEST(br-lan) 192.168.5.151 00:ff:48:b5:1c:e3
Fri Nov 18 18:04:50 2022 daemon.warn dnsmasq-dhcp[3551]: Ignoring domain ad.teltonika.lt for DHCP host name net-bliujuszy
Fri Nov 18 18:04:50 2022 daemon.info dnsmasq-dhcp[3551]: DHCPACK(br-lan) 192.168.5.151 00:ff:48:b5:1c:e3 net-bliujuszy
Fri Nov 18 18:04:51 2022 kern.info Leased 192.168.5.151 IP address for client 00:ff:48:b5:1c:e3 - net-bliujuszy in LAN
Logs on Windows side, however, do not indicate anything.
Fri Nov 18 18:04:47 2022 us=404840 TAP-WIN32 device [Ethernet 6] opened:
Fri Nov 18 18:04:47 2022 us=404840 TAP-Windows Driver Version 9.23
Fri Nov 18 18:04:47 2022 us=404840 TAP-Windows MTU=1500
Fri Nov 18 18:04:47 2022 us=411112 Successful ARP Flush on interface [3] {48B51CE3-7118-499F-A271-F81F93994F6E}
Fri Nov 18 18:04:47 2022 us=411112 Data Channel MTU parms [ L:1576 D:1450 EF:44 EB:398 ET:32 EL:3 ]
Fri Nov 18 18:04:47 2022 us=411112 Local Options String (VER=V4): 'V4,dev-type tap,link-mtu 1576,tun-mtu 1532,proto UDPv4,cipher BF-CBC,auth SHA1,keysize 128,secret'
Fri Nov 18 18:04:47 2022 us=411112 Expected Remote Options String (VER=V4): 'V4,dev-type tap,link-mtu 1576,tun-mtu 1532,proto UDPv4,cipher BF-CBC,auth SHA1,keysize 128,secret'
Fri Nov 18 18:04:47 2022 us=411112 TCP/UDP: Preserving recently used remote address: [AF_INET]X.X.X.X:1194
Fri Nov 18 18:04:47 2022 us=411112 Socket Buffers: R=[65536->65536] S=[65536->65536]
Fri Nov 18 18:04:47 2022 us=411112 UDP link local: (not bound)
Fri Nov 18 18:04:47 2022 us=411112 UDP link remote: [AF_INET]X.X.X.X:1194
Fri Nov 18 18:04:47 2022 us=520510 Peer Connection Initiated with [AF_INET]X.X.X.X:1194
Fri Nov 18 18:04:53 2022 us=85629 TEST ROUTES: 0/0 succeeded len=0 ret=1 a=0 u/d=up
Fri Nov 18 18:04:53 2022 us=85629 WARNING: this configuration may cache passwords in memory -- use the auth-nocache option to prevent this
Fri Nov 18 18:04:53 2022 us=85629 Initialization Sequence Completed
Fri Nov 18 18:04:53 2022 us=85629 MANAGEMENT: >STATE:1668787493,CONNECTED,SUCCESS,,X.X.X.X,1194,,
Could you SSH into your RUT240, execute command logread -f, then restart the VPN connection to check if DHCP discovery is received from Windows side?
Could you also try disabling your computer's firewall, to eliminate possibility of it interfering?
Maybe you could reset the device to factory defaults and reconfigure only VPN connection, to check if previous firmware updates, if they were performed, or other configurations do not interfere to DHCP operation?
Best regards,