I get some troubles with dhcpd. It takes a long time till some of the clients are served! Sometimes not at all, and I have to reboot the client to get it to work. I would like to understand the log file more. Below are the last entries of dhcpd.
What means Ping timeout: 1 ? What can I do? What does DHCPACK means after the DHCPREQUEST? What means DHCPDISCOVER? ..... What means (WGR614v4) via eth3 ? As you can see the entries for some of the clients repeats all the time, why?
Oct 22 09:19:12 dns dhcpd: DHCPREQUEST for 192.168.250.100 from 00:0e:7a:69:08:0b via eth3 Oct 22 09:19:12 dns dhcpd: DHCPACK on 192.168.250.100 to 00:0e:7a:69:08:0b via eth3 The client is requesting 192.168.250.100 -- probably it was assigned
Ronald Wiplinger
Oct 22 09:19:41 dns dhcpd: DHCPDISCOVER from 00:0f:d3:00:0c:b5 via eth3 Oct 22 09:19:41 dns dhcpd: Ping timeout: 1 Oct 22 09:19:42 dns dhcpd: DHCPOFFER on 192.168.250.112 to 00:0f:d3:00:0c:b5 via eth3 Here the client is hunting for any DHCP server it can find, and at the same time it is requesting a brand new IP. The server selects an IP from its pool and checks (ICMP Ping) to see if the IP is in use; it is not (ping timeout), so the server offers the IP to the client. You do not need to worry about the Ping timeout, it is quite normal.
[Sidebar comment: You *do* need to worry if you see a "ping" here that did -not- timeout, because that would mean the DHCP server has an IP listed as "free" in its pool, but the IP is actually in use somewhere in the network. Restarting all the clients should resolve such a problem (no need to reboot, just restart their DHCP client scripts).] The very next thing that should happen is that the client announces it accepts the IP (by sending a DHCPREQUEST to the server), or refuses it (with a DHCPDECLINE). Neither of these happens, so the OFFER message is not getting to the client at all. About a minute later, the client starts again with a brand new DISCOVER message, which makes me think the client's firewall is blocking incoming DHCP traffic. Check your firewall on this client to make sure that TCP and UDP ports 67 and 68 (bootps and bootpc) are open for incoming traffic (also see below).
Oct 22 09:20:12 dns dhcpd: DHCPREQUEST for 192.168.250.100 from 00:0e:7a:69:08:0b via eth3 Oct 22 09:20:12 dns dhcpd: DHCPACK on 192.168.250.100 to 00:0e:7a:69:08:0b via eth3 This IP was assigned to the same client only a minute ago; as Ulf says, your lease time is only 60 seconds. Check the DHCP server config file and set it to 86400 (seconds, or one day).
Oct 22 09:20:44 dns dhcpd: DHCPDISCOVER from 00:0f:d3:00:0c:b5 via eth3 Oct 22 09:20:44 dns dhcpd: Ping timeout: 1 Oct 22 09:20:45 dns dhcpd: DHCPOFFER on 192.168.250.112 to 00:0f:d3:00:0c:b5 via eth3 Oct 22 09:21:12 dns dhcpd: DHCPREQUEST for 192.168.250.100 from 00:0e:7a:69:08:0b via eth3 Oct 22 09:21:12 dns dhcpd: DHCPACK on 192.168.250.100 to 00:0e:7a:69:08:0b via eth3 This is what the sequence should look like when a client starts with a DISCOVER message. This client most likely is not giving you any problems at all.
If you are using the ISC dhclient/server you will have package dhcp installed (the common files used by both client and server packages). This package includes RFC 2131, which is the RFC for DHCP stuff. It might help to read this document in conjunction with the manpages for your client and server. Also examining the DHCP lease file (which is in /var/lib/dhcp/) should give you some assistance in properly configuring your server. And finally, make sure your firewall isn't blocking the ports DHCP uses -- 67 and 68, for both tcp and udp. If you are using SuSEfirewall2, there should not be any problems (it's what I use), unless you are specifically blocking port 67 for INPUT.