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Forum Discussion
Command to Log DHCP ?
In the past, the ORBI log included every time a DHCP address was issued by the router. I had noticed that some devices seemed to be issued DHCP addresses OFTEN (like, every 5 minutes). The log no longer shows anything about DHCP. Is there a way to get the log file to show DHCP activity? (a Telnet command?) Thanks
3 Replies
CrimpOnwrote:In the past, the ORBI log included every time a DHCP address was issued by the router. I had noticed that some devices seemed to be issued DHCP addresses OFTEN (like, every 5 minutes). The log no longer shows anything about DHCP. Is there a way to get the log file to show DHCP activity? (a Telnet command?) Thanks
I don't believe this activity is logged, perhaps somebody else can correct me if a log file is available - but I doubt it.
However, you can capture all DHCP traffic readily enough. This may be more helpful to you since you'll have both sides of the conversation and implicitly see all DHCP activity. The Orbi's are just a (sloppily) customized OpenWRT system under the hood and they include tcpdump. I've had to use it many times chasing down different issues.
Assuming your Orbi is in "routed" mode (meaning the router provides the DHCP server), here's how you would capture DHCP traffic for analysis.
1. Telnet into the router (NOT SATTELITE). It sounds like you already know how to do this.
2. Use the following command
tcpdump -i any -n port 67 and port 68
You'll see all the DHCP traffic heard on any interface. You can send it to a pcap file if you want to use it with wireshark or something a little more user-friendly, but I assume you'll only be dealing with a few pages of text.
Good luck. I suspect you'll find the source of your problem is instability in the layer 2 backhaul between the access points caused by bugs in the firmware.
DHCP logging is working by default for me. See attached image. 2.1.2.18
Hmmmm. After many (many) days of not seeing any DHCP activity in the log, there were some this morning (Sunday). I will continue to look at logs to see when devices are doing DHCP. I don't see anything in the documentation about how long ORBI DHCP leases are for. If I remember correctly, devices ask to renew their lease when half of the lease time has expired. Could ORBI be issuing leases good for weeks?
t_k_Aprentice was correct. The text stream is somewhat of a challenge to read through. I have Wireshark, and it would be easier to use. My linux days are long past, and I'm not exactly certain how to dump to a pcap file and then transfer the file to my Windows machine.
