RED seems online but does not provide internet access

Question

Hello there! 
 I am facing a problem with one of our RED10s at the moment. 
 It is configured in Standard/Unified - mode (and has always been since 2014) in order to connect to our UTM9 ASG220. It just stopped working properly this afternoon. 
 It is still listed online in the RED - Management menu and the RED livelog shows no conspicuities. Even after changing the UTM hostname in the RED-options for this one only made it disconnect for a few seconds before it reconnected and looked just well again on the dashboard. 
 But still, if I put a device right behind the RED it does not receive an IP address = will not have internet access. 
 I also can not ping the RED's IP address (192.168.25.254) from the UTM-network. I can ping any other RED's IP-address and get responses. 
 
 Does anyone know about this issue and would help me, please? 
 
 Thank you very much in advance! 
 
 Best Regards 
 Sebastian

sachingurung · Answer

Hi Sebastian, 
 Greetings. 
 If the RED shows connected with UTM, capture a TCPDUMP in UTM. 
 With root privileges, type command: 
 consolve> tcpdump -nei any host <RED connection IP> and port 3400 
 Monitor the communication on port 3400. If no packets are received on UTM over 3400, I suspect ISP blocking 3400 communication port for RED 10. 
 Refer this link to check TCP/UDP Ports used by Sophos RED: 
 www.sophos.com/.../122755.aspx 
 Next, check if the DHCP Server for the concerned RED is Active. 
 Let me know if that helps. 
 Thanks 
 Sachin Gurung