Računalnike naključno izkaplja iz mreže

Imamo ADSL skozi strežnik, ki deluje kot router/firewall/web-strežnik/dhcp... z Mandrake 10.0 Linuxu, nato pa gre povezava na switch/hub in nato na vse ostale računalnike na katerih so Windows XP-ji.

Problem:
Včasih eden od računalnikv naključno pade z mreže (lokalne in interneta), pri tem pa vsi ostali računalniki ostanejo priključeni in delujejo normalno (in to nikoli ne zgodi strežniku).
Če resitiram računalnik se normalno priključi nazaj na mrežo, zgodi pa se pa popolnoma naključno, včasih par dni ne, včasih pa 2-3 na dan.

Včasih vzporedno zamrzne glasba na Winamp!
Ponavadi pade z mreže čez noč, ko pustim prižgan računalnik in eMule v teku...

Če bi kdo slučajno imel kakšno misel kaj bi bilo lahko krivo, ker se meni niti ne sanj kje iskati krivca!!!
Mogoče je DHCP na strežniku (da ko poteče licenca izklopi računalnik iz mreže) ali pa nima dhcp pravilno odprtih portov na Shorewall Firewall?
Je mogoče kriv switch/hub (Mercury KOB SDH8P) ali mrežne kartice na računalniku?

Hvala za pomoč!!

Imam statični IP za ADSL...

Statičnih IP za notranje omrežje, pa rajši ne bi nastavljal, ker nekateri uporabljajo računalnike tudi v drugih omrežjih in bi morali za vsak preklop na novo nastavljati svoj IP.

Na DHCP strežniku sem podaljšal "lease" - čas, za dodeljen IP
(prejšnji je bil na 6 ur) - mogoče bi bilo ti krivo, da je potekel "lease" in se ni mogel računalnik na windowsih nazaj prkiklopiti...
(ko pa resetiraš se ti dodeli novo dovoljenje/"lease")

QL, hvala za idejo!
Bom preiskusil...

Tečno je samo, ker moreš čakati več ur ali dni, da se ti izklopi, da vidiš če je nekaj krivo...

k0lar, ali mislis da v celoti padejo iz omrezja, ali pa da preneha delovati file and printer sharing? uporaba programov, ki koristijo prenos podatkov cez omrezje nebi smela vplivat na prekinjanje povezave iz omrezja, neglede na stevilo povezav na casovno enoto ali prenesenih podatkov, razen ce temu nasprotuje pozarni zid. no kakorkoli ze, ko racunalnik izklopi iz omrezja, preveri ce dobis odziv od drugih racunalnikov povezanih na switch z ukazom ping. odziv bi moral dobiti, saj je prenos direkten. ce pa ni odziva, je pa problem pri dodeljevanju ip naslovov. torej problem z tvojim dhcp streznikom, ki je narobe konfiguriran. vsekakor priporocam da dodelis staticne ipje vsem racunalnikom.

aja pa ce ti prekine samo za kratek cas (siol style), pomeni da ti dhcpd zamenja ip. tako da povecaj lease time ali si pa nastimaj staticni ip.
Pravilno konfiguriran dhcpd.conf za domace omrezje je taksen:
-----------------------------------------------------------------
default-lease-time 600;
max-lease-time 7200;
option subnet-mask 255.255.255.0;
option broadcast-address 192.168.0.255;
option routers 192.168.0.1;
option domain-name-servers 193.189.160.11, 193.189.160.12;
option domain-name "the-nox.com";
ddns-update-style ad-hoc;

subnet 192.168.0.0 netmask 255.255.255.0 {
range 192.168.0.20 192.168.0.200;
}

host bond {
hardware ethernet 00:50:BF:79:4D:39;
fixed-address 192.168.0.12;
}
host korenje {
hardware ethernet 00:50:8D:53:81:38;
fixed-address 192.168.0.11;
}
--------------------------------------------------------------

potem pa pozenes: /usr/sbin/dhcpd eth1;


root@skum:~# arp -i eth1 -a
korenje (192.168.0.11) at 00:50:8D:53:81:38 [ether] on eth1
bond (192.168.0.12) at 00:50:BF:79:4D:39 [ether] on eth1

se strokovna razlaga:

Leases
DHCP leases addresses, meaning it assigns addresses for a limited period. Halfway through the lease period, the client sends a direct message to the DHCP server in an attempt to renew the lease. If the DHCP server is available, it sends the client a lease renewal. Otherwise, the client tries again at one-half of the time remaining on the lease, and so on. For a 3-day lease (72 hours), the client tries to renew at 36 hours, then 54 hours, then 63 hours. Finally, the client tries a broadcast for any DHCP server. If the client doesn't find a server before the lease expires, the computer can no longer run TCP/IP.

As long as a client remains connected or reconnects before the lease expires, the client retains an IP address. But if a client lets the lease expire (i.e., doesn't connect for a period of time), DHCP recovers that address and makes it available for another client to use. The lease-recovery process doesn't happen immediately after lease expiration; it can take several times the lease length. In a fairly stable environment, you might want to set the lease for 3 or 4 days. This length of time lets users turn off their computers over a long weekend without losing their IP addresses, and lets DHCP recover an IP address within a few days if you remove a computer from the network. However, if your sales staff share office space and use their onsite computers only a few hours once a week, you might want to set the lease duration for just 4 or 6 hours. This method lets DHCP release IP addresses for the next day. If you don't move your machines around a lot, you might think you need to assign leases permanently. However, DHCP won't recover an unlimited lease if you remove the computer from the network.

Because the DHCP lease-request process relies on broadcasts and broadcasts don't pass through routers, you might wonder whether you need a DHCP server (which implies an NT server) on every subnet. Fortunately, the answer is no. You can configure an NT workstation as a DHCP relay agent. You need only one workstation per subnet. First, you must add the DHCP relay agent as a network service. Then, you configure it with the DHCP server's IP address. When the relay agent hears a DHCP request, the agent forwards the request directly to the server. Thus, the relay agent acts as a go-between for the client, and the client receives an IP address. The DHCP server knows which subnet the request came from, and the server assigns an address from the correct scope for that subnet.

Računalnik v celoti pade z omrežja...lokalnega omrežja in interneta (za čuda se mi windowsi NE pojamrajo v stilu "Network cable unplugged")...povezave preprosto ni! Reši ga sam reboot!

DHCP strežnik me ne bi smel izklopiti, ker imam nastavljeno
"Lease length for BOOTP clients - Forever" in
"Lease end for BOOTP clients - Never"
...kar naj bi pomenilo, da ne menja IP dokler sem priključen na mrežo/prižgan računalnik

Lease sem pa podaljšal na:
Default lease time - 172800
Maximum lease time - 345600
to naj bi bilo 4 dni
(to sem nastavil včeraj, ampak me je danes zopet izklopilo)

Bi znal biti problem v Windowsih XP?
Mam vse windows popravke (SP2), redno poganjam Ad-Aware, SPybot, Registry First Aid, Kasparsky Antivirus...
(Nisem še testiral da bi pustil na enem računalniku teči Linux, da vidim, če bi tudi v tem primeru izklopil...)

Hecno je - sicer ne vem če je povezava in verjetno je - da vedno vzporedno ko me vrže z mreže zablokira zvok (v loopu piska zadnji ton preden zašteka...zelo moteče) - kar se pa pri drugih ne naredi...

Mel sem iste težave z routerjem (potem sem nekje prebral, da je ven metalo, ker je bil router testiran samo z 256 vporednimi povezavami, kar pa smo v večimi eMuli hitro napolnili)...ko sem vklopu in izklopu router je pa delal naprej normalno...ko sem pa zgubil živce sem rajši šel na server...
Kako bi se na linux serverju to dalo mogoče spremenit (dovoljeno število povezav)???

ko te vrze iz omrezja, poglej kateri ip imas. napisi ipconfig v ms-dos prompt. sicer je pa mozno da je problem z mreznimi karticami. jz sm mel probleme z via-rhine. z real-tekovimi nikoli ne gre narobe.