Hi,

I am experiencing a very strange network problem and I hope somebody can help me. I have two laptops at home that are linked as a small network. The first one is connected with my ISP through the eth0 and with the second laptop through a PCMCIA-eth1 (3com). The second laptop (the client) is connected through the eth0 with the first one (the server).

Earlier, the first laptop (server) used to run Fedora 1 and the second (the client) used to run Red Hat 9. Everything worked fine. I upgraded both computers and they run now Fedora Core 2. Now when I turn on the computers, the network works for something like 25 minutes and then dies and I am not able to re-establish it. Even stranger is the fact that I am only able to connect the two computers again in the morning after.

The connection between the first laptop and the external world (ISP) continues to work even after the network between both computers died.

The network is build as follows:

Network: 192.168.0.0
Computer 1: 192.168.0.1 (static IP), runs also a dhcp server, a IP-masquarade, and (I think) a DNS sever (I follow a network how-to and configured the file named.conf).
Computer 2: obtains an IP automatically (dhcp) --- used to be always 192.168.0.58, but is now always 192.168.0.60

While the network is running (for 25 minutes...), I am able, from the client computer, to ping the server (192.168.0.1) and also the ISP. And I have access to the web, email etc. But only for 25 minutes.

Thank you very much,

PS. I have already tried to use a static IP in the client too (192.168.0.2). This also works for only 25 minutes...

What kernel are you using? Are there any clues in /var/log/messages?

Hi,
I'm using kernel version 2.6.5-1.358 (Fedora Core 2) and unfortunately I didn't find any clues in /var/log/messages (neither on the server nor on the client).
I don't know what to do.

Maybe your lease times have expired since you said the first laptop provides DHCP for the second laptop. If the second laptop does not ask the first laptop to renew its IP it will expire after a certain period of time(laptop 1 will not allow access to laptop2<-that maybe your problem). That is the only thing i can think of that has to do with time in your situation.

Open your DHCP configuration file and look at the default lease times. if your unsure post your dhcpd.conf file here.

Hi,
thank you very much for your answer. The "lease" time from my dhcpd.conf is 86400 (that is one day, right?). But is this time also valid if I use a static IP for the client? I ask because the network also dies when I tried to use a static IP. Should I increase the lease time?
My dhcpd.conf file is as follows:

ddns-update-style ad-hoc;
default-lease-time 86400;
max-lease-time 86400;
option routers 192.168.0.1;
option ip-forwarding off;
option broadcast-address 192.168.0.255;
option subnet-mask 255.255.255.0;
option domain-name-servers 192.168.0.1;
subnet 192.168.0.0 netmask 255.255.255.0 {
range 192.168.0.2 192.168.0.60;
}

Thank you very much.

ya i think 86400 thats one day.

My default-lease-time is 600, and my max-lease-timeis 7200; basically it renews the IP every 10 minutes which is fine with me because i havent had any problems. Try using those and post again if it doesn't work again.


Static IP's are not the same They do not need to renew there IP since it is fixed and does not change over a period of time.

Hi,
thank you for your answer. I made the changes in my dhcpd.conf file. But I am not able to see if it works, since once my network dies I can re-establish it only in the next day... (very, very strange!).
But since the problem occurs with dhcp and also with static IP, I don't think the cause is the lease time. But I will test it tomorrow and I will post an answer.
Thank you again.

Hi,
the changes on the "lease times" didn't have any effect. On the other hand, I installed a pcmcia ethernet card on the client and now it works!! With the built-in network adapter the network still runs for only 25 minutes. With the pcmcia, it runs all day...
Although I don't know why, my problem is partially solved (although I would like to use my built-in network too).
Thanks again for all posts. And if anybody has a clue why the network runs without problems with the pcmcia, but only for 25 minutes with the built-in adapter, I would like to know.
Thank you.

Have you checked the link light on the built-in ethernet card? If it is not on then maybe the problem is hardware related, either with the cable or the ethernet card.

A temporary solution is better than no solution.