Hello,
I seeking solutions on the following problem:
When the client restart own modem, (or loses power) and behind the modem there is a home-router (tplink, linksys, etc),
then it happens, that client machines (behind router) lose the internet connection.
This time customer must to release/renew on their router, or reboot the router also.
But this not really comfortable for the customers.
I try increase the max-cpe counter in modem-konfig without success.
I use static host declarations with 3 hours lease time.
It is not clear where i need modify: in cmts or dhcpd.conf or in modem config?
I can post conf-snipplet if need.
Many thanks for help.
Sounds if DHCP-Source Verifiy is configured on the CMTS but not DHCP-Lease-Querry.
e.g. on the Cisco bundle interface:
cable source-verifyinstead
cable source-verify dhcpSo, if the cable modem goes offline but the CPE will not recognize it the CPE try to make IP traffic still with the previous received IP Address. But during the offline of the cable modem the CPE entries on the CMTS will go away. So the IP Address of the CPE is not still valid until the DHCP process restarts (due DHCP Release/Renew or reboot of the CPE) and the CMTS can verify the CPE IP Address through DHCP-Snooping. The DHCP-Lease-Query should solve the problem and the CMTS will ask the DHCP Server if the IP Address of the CMTS is valid.
Maybe you will tell us the CMTS model which you use.
Best regards,
wittmann
Hi,
In my CMTS config now there is following row (on Bundle1):
cable source-verify dhcp server a.b.c.d (a.b.c.d = ip address of dhcp-server)
So is it not good?
So, it should work. Maybe you should investigate the DHCP-Messages between the CMTS and DHCP-Server. Maybe the communication is not right. Just a hint.
bet regards,
wittmann
No, there is no DHCPLEASEQUERY in dhcpd.log. (only DHCPINFORM)
I tried 'tshark -f "udp"', nothing silimar dhcp message.
But in the dhchp.log there is a lot of:
... dhcpd: Received DHCPv4 packet without client-id option and empty hlen field.
messages, and i dont know why.
I added the above line to the cmts config, and now i see the incoming DHCPLEASEQUERY requests...
dhcpd: Received DHCPv4 packet without client-id option and empty hlen field.
dhcpd: DHCPLEASEQUERY from 172.16.255.254 for IP A.B.C.D
dhcpd: DHCPLEASEUNKNOWN to 172.16.255.254 for IP A.B.C.D (0 associated IPs)
dhcpd: Received DHCPv4 packet without client-id option and empty hlen field.
dhcpd: DHCPLEASEQUERY from 172.16.255.254 for IP A.B.C.E
dhcpd: DHCPLEASEUNKNOWN to 172.16.255.254 for IP A.B.C.E (0 associated IPs)
dhcpd: Received DHCPv4 packet without client-id option and empty hlen field.
dhcpd: DHCPLEASEQUERY from 172.16.255.254 for IP A.B.C.F
dhcpd: DHCPLEASEUNKNOWN to 172.16.255.254 for IP A.B.C.F (0 associated IPs)
dhcpd: Received DHCPv4 packet without client-id option and empty hlen field.
but, i think this is impasse, because i use static host decl. and it appears that
isc dhcp (4.2.5) do not manage this, he send DHCPLEASEUNKNOWN message, despite of
these host decl exist in the dhcpd.leases file...
Possibly need to patch isc dhcp server?