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I have added some context to my question incase this is helpful but please feel free to just answer the question at the bottom.

I have a TP-Link router that keeps crashing but in two stages, first the DHCP, web management and remote log saving become nonfunctional then about 2 hours after this the router becomes of less use than a lobster, that is it responds to no form of outside input that I could think of, until it is rebooted.

Immediately before the first stage of the crash the router logs the following events (captured using the remote save system log function:)

11/04/2015 11:25:27 <13> DHCPC: Send DISCOVER with request ip 0.0.0.0 and unicast flag 1 11/04/2015 11:25:30 <13> DHCPC: Send DISCOVER with request ip 0.0.0.0 and unicast flag 1 11/04/2015 11:25:33 <13> DHCPC: Send DISCOVER with request ip 0.0.0.0 and unicast flag 1 11/04/2015 11:25:38 <13> DHCPC: Send DISCOVER with request ip 0.0.0.0 and unicast flag 0 11/04/2015 11:25:41 <13> DHCPC: Send DISCOVER with request ip 0.0.0.0 and unicast flag 0 11/04/2015 11:25:44 <13> DHCPC: Recv no OFFER, DHCP Service unavailable

My Question is: Can/Should a DHCP server send a DISCOVER message? As it was my understanding based on http://tools.ietf.org/html/rfc2131 that servers should only receive DISCOVER.

Many thanks in advance for any help.

closed as off-topic by Ron Trunk, Teun Vink, Mike Pennington, YLearn Apr 11 '15 at 14:40

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "NE is a site for to ask and provide answers about professionally managed networks in a business environment. Your question falls outside the areas our community decided are on topic. Please visit the help center for more details. If you disagree with this closure, please ask on Network Engineering Meta." – Ron Trunk, Teun Vink, Mike Pennington, YLearn
If this question can be reworded to fit the rules in the help center, please edit the question.

  • A server should not send a Discover message. Another clue/oddity is the log message starts with "DHCPC" which usually indicates a client. Have you tried a packet capture? – Ron Trunk Apr 11 '15 at 10:50
  • (Apologies for the delay just had to reboot) Hi @Ron, thanks for clearing this up. I have not tried a packet capture as I have never been capturing at the right time. – o.comp Apr 11 '15 at 10:58
  • Not sure if this helps (I don't imagine it would) but TP-Link publish their GPL code and the file of source code with produces the 'Send DISCOVER' if availilble here – o.comp Apr 11 '15 at 11:09
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    The router may send discover messages if it is acting as a client on a WAN link, for example. The fact that it is not receiving a reply should be investigated. – Ron Trunk Apr 11 '15 at 11:12
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    Also, as this appears to be a home network, this subject is unfortunately off-topic on this forum. You might get a better answer on Superuser. – Ron Trunk Apr 11 '15 at 11:13
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It's acting as a dhcp relay agent.

This is a feature that is used to offer IP addresses for subnets that the current DHCP server is not offering.

This feature should generally have an off or on setting and is generally something a router does.

It is useful if the actual DHCP server for a segment is, for example, on a different VLAN.

If there is a server answering the DHCPDISCOVER message a DHCPOFFER is sent unicast to the DHCP-relay on port 67 UDP. The DHCP-relay agent then broadcasts the DHCPOFFER to a subnet using UDP port 68.

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