Linux

Hi guys,

I just wanted to know is there any way we can know that the linux has renew it's lease time..

My network has configuration that gives the same IP every time u renew the IP. So when it automatically checks or send the query to the dhcp server for the renewal of the IP ( when the lease time reached to the 50% ) I am not able to know whether it has renewed or not.

Your DHCP server (assuming your DHCP server also runs Linux this would be dhcpd) should be configured to keep logs, where you should find the information about when it gave out a particular address to a particular machine the last time.

Your DHCP client daemon (dhclient) also keeps a log file under /var/lib/dhcpd/dhclient.leases where all the current leases it has been assigned are noted.

See the manpage for dhclient.leases(5) or dhclient(8) and dhcpd.conf(5) respectively for details and read RFC2132 (Droms et al., 1997) and/or RFC2131 (Droms, 1997) for a detailed description about the DHCP process. Note that RFC1533 (Droms et al., 1993) and RFC1534 (Droms, 1993) are obsoleted.

I hope this helps.

bakunin

lease {
interface "eth0";
fixed-address 10.101.1.133;
filename "pxelinux.bin";
option subnet-mask 255.255.255.0;
option routers 10.101.1.1;
option dhcp-lease-time 1209600;
option dhcp-message-type 5;
option domain-name-servers 192.168.6.4,203.88.135.250,203.90.66.79,202.138.103.100,192.168.6.2;
option dhcp-server-identifier 192.168.6.15;
option broadcast-address 10.101.1.255;
renew 2 2008/10/21 13:15:26;
rebind 2 2008/10/28 08:33:17;
expire 4 2008/10/30 02:33:17;
}

I use check the file you have mention. And I got the information reqiuire. But I wanted to know after it reaches the time of renewal it really query for for the another lease time or not.

So what i did is change the time to 2008/10/21 13:15:00 and waited till 13:16 but even after then the dhclient.leases time shows the same date/time for the renew, rebind and expier. Is that mean it hasn't query for the renewal.

I don't know anything about this, Will be thankful if you will spot some light on this,

Thanx in advance.

Perhaps so. Otherwise the log file wouldn't make much sense, yes?

The best advice i can give you is to read the RFCs i mentioned. The inner workings of the DHCP protocol, the messages passed back and forth between the client and server parts, etc. are all laid out there.

RTFM and be enlightened.

I hope this helps.

bakunin