Problem sa DNS-om

Pozdrav svima,

evo instalirao sam jedan ubuntu 8.04 koji šeruje internet konekciju (ADSL) u LAN i stvar radi preko FIrestartera i dnsmasq-a… i dchp3-servera. Međutim pojavio mi se sada problem da kada pristupam preko tog ubuntua i kada neko vrijeme čitam neku stranicu i pođem da otvaram druge linkove na njoj stranica jednostavno ne bude dostupna. Ja pretpostavljam da sve to ima nekakve veze sa DNS keširanjem, ali nemam ideju kako da riješim problem :frowning:

p.s.

testiram kompjutere u LAN-u i čini mi se da ne prave isti problem… ali još ne mogu reći sa sigurnošću.

Pozdrav,

Ako ti racunar otvori prvi stranicu normalno ne bi trebao biti dns problem.
Ako sam dobro shvatio kada otvoris stranicu pa neko vrijeme citas sadrzaj stranice bez aktivnosti na internetu pa zatim kliknes neki link na stranici dobijes info. da stranica nije dostupna.

Radi li ti net uopce tada ili ne.

ne radi mi u tim momentima, čitao sam log adsl modema i piše mi da su bila samo 2 prekida a kvar je konstantan… vjerujem da je ovo ipak do dnsmasq-a samo nemam pojma gdje bi moglo biti…

Recimo neće da proslijedi zahtjev nekih 5 sekundi i nakon rifrešanja ponovo otvori… do sada nisam recimo osjetio pucanje IRC-a ili MSN-a tako da sam uvjeren da ima veze sa DNS-om…

možeš li pingati po IP adresi?
šta ti je na klijentskim mašinama u /etc/resolv.conf

nameserver 192.168.20.1 u klijenata u resolv.conf

provjerit ću dali pinga…

čini se da pinga bez problema

update…

ne pinga bez problema, u momentima kad crkne internet ne pinga ip adrese prevedene pomoću DNS-a

64 bytes from mu-in-f99.google.com (209.85.135.99): icmp_seq=56 ttl=51 time=72.2 ms
64 bytes from mu-in-f99.google.com (209.85.135.99): icmp_seq=57 ttl=51 time=72.3 ms
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
^[[Aping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
64 bytes from mu-in-f99.google.com (209.85.135.99): icmp_seq=68 ttl=51 time=77.6 ms
64 bytes from mu-in-f99.google.com (209.85.135.99): icmp_seq=69 ttl=51 time=73.0 ms
64 bytes from mu-in-f99.google.com (209.85.135.99): icmp_seq=70 ttl=51 time=73.1 ms
64 bytes from mu-in-f99.google.com (209.85.135.99): icmp_seq=71 ttl=51 time=72.8 ms

istu stvar radi kad pingam čistu IP adresu

64 bytes from 209.85.135.99: icmp_seq=78 ttl=51 time=72.2 ms
64 bytes from 209.85.135.99: icmp_seq=79 ttl=51 time=73.3 ms
64 bytes from 209.85.135.99: icmp_seq=80 ttl=51 time=73.0 ms
64 bytes from 209.85.135.99: icmp_seq=81 ttl=51 time=72.6 ms
64 bytes from 209.85.135.99: icmp_seq=82 ttl=51 time=73.8 ms
64 bytes from 209.85.135.99: icmp_seq=83 ttl=51 time=72.7 ms
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
ping: sendmsg: Network is unreachable
64 bytes from 209.85.135.99: icmp_seq=103 ttl=51 time=73.3 ms
64 bytes from 209.85.135.99: icmp_seq=104 ttl=51 time=72.9 ms
64 bytes from 209.85.135.99: icmp_seq=105 ttl=51 time=72.6 ms
64 bytes from 209.85.135.99: icmp_seq=106 ttl=51 time=73.8 ms
64 bytes from 209.85.135.99: icmp_seq=107 ttl=51 time=73.7 ms

kao da internet stvarno pada… :S

evo i system log od modema

6/23/2009 12:27:11> SNMP TRAP 3: link up
6/23/2009 12:27:33> SNMP TRAP 2: link down
6/23/2009 19:40:30> Last errorlog repeat 1 Times
6/23/2009 19:40:33> ppp_ready: ch:80503fb8, iface:8044db2c
6/23/2009 19:40:33> SNMP TRAP 3: link up
6/23/2009 19:40:33> Accept() fail
6/23/2009 19:40:33> Accept() fail
6/23/2009 21:30:12> SNMP TRAP 2: link down
6/23/2009 21:30:15> ppp_ready: ch:80503fb8, iface:8044db2c
6/23/2009 21:30:15> SNMP TRAP 3: link up
6/23/2009 21:30:15> Accept() fail
6/23/2009 21:30:15> Accept() fail
6/24/2009 7:7:52> SNMP TRAP 3: link up
6/24/2009 7:9:20> SNMP TRAP 2: link down
6/24/2009 7:9:21> SNMP TRAP 3: link up
6/24/2009 9:5:58> sending request to NTP server(697d2)
6/24/2009 9:5:59> received from NTP server(697d3)
6/24/2009 9:2:33> Adjust time to 4a41eba9
6/24/2009 9:2:33> adjtime task pause 1 day

Pretpostavljao sam tako nesto jer da je do DNS-a ne bi radio nikako.

Koliko vidim podesen ti je racunar da pusti vezu ako nema aktivnosti odredjeni period, ili ne?

Ako jeste onda pokusaj podesiti da stalno drzi vezu pa nece biti prekida to ti je jedna varijanta.

Ovaj mi log zapravo nista ne kaze, samo da je u odredjeno vrijeme uspostavljena veza i pustena.

Probaj tail -f /var/log/messages mozda nesto vise bude tu.

evo loga

Jun 24 12:25:15 server dhcdbd: message_handler: message handler not found under /com/redhat/dhcp/eth3 for sub-path eth3.dbus.get.reason
Jun 24 12:26:57 server dhcdbd: message_handler: message handler not found under /com/redhat/dhcp/eth3 for sub-path eth3.dbus.get.reason
Jun 24 12:28:38 server dhcdbd: message_handler: message handler not found under /com/redhat/dhcp/eth3 for sub-path eth3.dbus.get.reason
Jun 24 12:29:03 server kernel: [ 1646.297636] Inbound IN=eth3 OUT= MAC=00:19:5b:5b:b6:51:00:04:ed:a0:d2:f2:08:00 SRC=69.89.20.51 DST=192.168.1.100 LEN=1482 TOS=0x00 PREC=0x00 TTL=52 ID=63563 DF PROTO=TCP SPT=80 DPT=2805 WINDOW=6970 RES=0x00 ACK URGP=0
Jun 24 12:29:32 server kernel: [ 1674.666172] Inbound IN=eth3 OUT= MAC=00:19:5b:5b:b6:51:00:04:ed:a0:d2:f2:08:00 SRC=69.89.20.51 DST=192.168.1.100 LEN=1482 TOS=0x00 PREC=0x00 TTL=52 ID=63564 DF PROTO=TCP SPT=80 DPT=2805 WINDOW=6970 RES=0x00 ACK URGP=0
Jun 24 12:30:19 server dhcdbd: message_handler: message handler not found under /com/redhat/dhcp/eth3 for sub-path eth3.dbus.get.reason
Jun 24 12:30:21 server kernel: [ 1723.997547] Unknown InputIN=eth0 OUT= MAC=ff:ff:ff:ff:ff:ff:00:16:cb:9b:9d:d0:08:00 SRC=0.0.0.0 DST=255.255.255.255 LEN=328 TOS=0x10 PREC=0x00 TTL=64 ID=0 PROTO=UDP SPT=68 DPT=67 LEN=308
Jun 24 12:30:22 server kernel: [ 1724.355890] Unknown InputIN=eth0 OUT= MAC=ff:ff:ff:ff:ff:ff:00:16:cb:9b:9d:d0:08:00 SRC=0.0.0.0 DST=255.255.255.255 LEN=328 TOS=0x10 PREC=0x00 TTL=64 ID=0 PROTO=UDP SPT=68 DPT=67 LEN=308
Jun 24 12:32:00 server dhcdbd: message_handler: message handler not found under /com/redhat/dhcp/eth3 for sub-path eth3.dbus.get.reason
Jun 24 12:32:21 server kernel: [ 1843.068179] Inbound IN=eth3 OUT= MAC=00:19:5b:5b:b6:51:00:04:ed:a0:d2:f2:08:00 SRC=69.89.20.51 DST=192.168.1.100 LEN=1482 TOS=0x00 PREC=0x00 TTL=52 ID=63566 DF PROTO=TCP SPT=80 DPT=2805 WINDOW=6970 RES=0x00 ACK URGP=0

Hmmm, izgleda kao problem sa dhcp-om, dnsmasq je dns forwarder i dhcp server a kako kažeš da si konfigurisao dhcp3 stoga možda je neki konflikt u pitanju.

pogledat ću… moguće da mi je pod dnsmasq-om upaljen dhcp, ali u tom slučaju dhcp3 nebi startao?! Vidjet ću malo da pročačkam, problem nestane kada se ugasi firestarter. s njegovim gašenjem prestane i šerovanje konekcije…

vidiću da sutra pozovem firestarter iz konzole pa da pratim u konzoli šta se događa u trenutku prekida…

Ako ti problem pravi firestarter vjerovatno su previše stegnuta firewall pravila, može li output komandi:

iptables -nvL iptables -t nat -nvL

[code]root@server:/home/administrator# iptables -nvL
Chain INPUT (policy DROP 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 ACCEPT tcp – * * 192.168.1.254 0.0.0.0/0 tcp flags:!0x17/0x02
36 9028 ACCEPT udp – * * 192.168.1.254 0.0.0.0/0
46 1932 ACCEPT all – lo * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT icmp – * * 0.0.0.0/0 0.0.0.0/0 limit: avg 10/sec burst 5
0 0 DROP all – * * 224.0.0.0/8 0.0.0.0/0
2 136 DROP all – * * 0.0.0.0/0 224.0.0.0/8
0 0 DROP all – * * 255.255.255.255 0.0.0.0/0
0 0 DROP all – * * 0.0.0.0/0 0.0.0.0
49 2284 DROP all – * * 0.0.0.0/0 0.0.0.0/0 state INVALID
0 0 LSI all -f * * 0.0.0.0/0 0.0.0.0/0 limit: avg 10/min burst 5
1424 981K INBOUND all – eth3 * 0.0.0.0/0 0.0.0.0/0
37 2479 INBOUND all – eth0 * 0.0.0.0/0 192.168.20.1
0 0 INBOUND all – eth0 * 0.0.0.0/0 192.168.1.100
21 4323 INBOUND all – eth0 * 0.0.0.0/0 192.168.20.255
0 0 LOG_FILTER all – * * 0.0.0.0/0 0.0.0.0/0
0 0 LOG all – * * 0.0.0.0/0 0.0.0.0/0 LOG flags 0 level 6 prefix `Unknown Input’

Chain FORWARD (policy DROP 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 ACCEPT icmp – * * 0.0.0.0/0 0.0.0.0/0 limit: avg 10/sec burst 5
38 2248 TCPMSS tcp – * * 0.0.0.0/0 0.0.0.0/0 tcp flags:0x06/0x02 TCPMSS clamp to PMTU
242 35199 OUTBOUND all – eth0 * 0.0.0.0/0 0.0.0.0/0
160 120K ACCEPT tcp – * * 0.0.0.0/0 192.168.20.0/24 state RELATED,ESTABLISHED
0 0 ACCEPT udp – * * 0.0.0.0/0 192.168.20.0/24 state RELATED,ESTABLISHED
0 0 LOG_FILTER all – * * 0.0.0.0/0 0.0.0.0/0
0 0 LOG all – * * 0.0.0.0/0 0.0.0.0/0 LOG flags 0 level 6 prefix `Unknown Forward’

Chain OUTPUT (policy DROP 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
22 968 ACCEPT tcp – * * 192.168.1.100 192.168.1.254 tcp dpt:53
37 2443 ACCEPT udp – * * 192.168.1.100 192.168.1.254 udp dpt:53
46 1932 ACCEPT all – * lo 0.0.0.0/0 0.0.0.0/0
0 0 DROP all – * * 224.0.0.0/8 0.0.0.0/0
7 432 DROP all – * * 0.0.0.0/0 224.0.0.0/8
0 0 DROP all – * * 255.255.255.255 0.0.0.0/0
0 0 DROP all – * * 0.0.0.0/0 0.0.0.0
49 2420 DROP all – * * 0.0.0.0/0 0.0.0.0/0 state INVALID
1494 235K OUTBOUND all – * eth3 0.0.0.0/0 0.0.0.0/0
48 7967 OUTBOUND all – * eth0 0.0.0.0/0 0.0.0.0/0
0 0 LOG_FILTER all – * * 0.0.0.0/0 0.0.0.0/0
0 0 LOG all – * * 0.0.0.0/0 0.0.0.0/0 LOG flags 0 level 6 prefix `Unknown Output’

Chain INBOUND (4 references)
pkts bytes target prot opt in out source destination
1344 962K ACCEPT tcp – * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
0 0 ACCEPT udp – * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
70 8317 ACCEPT all – * * 192.168.1.100 0.0.0.0/0
4 240 ACCEPT tcp – * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:53
15 1023 ACCEPT udp – * * 0.0.0.0/0 0.0.0.0/0 udp dpt:53
0 0 ACCEPT tcp – * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:5353
0 0 ACCEPT udp – * * 0.0.0.0/0 0.0.0.0/0 udp dpt:5353
0 0 ACCEPT tcp – * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:138
15 3855 ACCEPT udp – * * 0.0.0.0/0 0.0.0.0/0 udp dpt:138
0 0 ACCEPT tcp – * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80
0 0 ACCEPT udp – * * 0.0.0.0/0 0.0.0.0/0 udp dpt:80
0 0 ACCEPT tcp – * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:137
12 1008 ACCEPT udp – * * 0.0.0.0/0 0.0.0.0/0 udp dpt:137
0 0 ACCEPT tcp – * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:5750
0 0 ACCEPT udp – * * 0.0.0.0/0 0.0.0.0/0 udp dpt:5750
0 0 ACCEPT tcp – * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:139
0 0 ACCEPT udp – * * 0.0.0.0/0 0.0.0.0/0 udp dpt:139
0 0 ACCEPT tcp – * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:445
0 0 ACCEPT udp – * * 0.0.0.0/0 0.0.0.0/0 udp dpt:445
0 0 ACCEPT tcp – * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:5272
0 0 ACCEPT udp – * * 0.0.0.0/0 0.0.0.0/0 udp dpt:5272
0 0 ACCEPT tcp – * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:1405
0 0 ACCEPT udp – * * 0.0.0.0/0 0.0.0.0/0 udp dpt:1405
0 0 ACCEPT tcp – * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:38244
0 0 ACCEPT udp – * * 0.0.0.0/0 0.0.0.0/0 udp dpt:38244
0 0 ACCEPT tcp – * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:1871
0 0 ACCEPT udp – * * 0.0.0.0/0 0.0.0.0/0 udp dpt:1871
22 10717 LSI all – * * 0.0.0.0/0 0.0.0.0/0

Chain LOG_FILTER (5 references)
pkts bytes target prot opt in out source destination

Chain LSI (2 references)
pkts bytes target prot opt in out source destination
22 10717 LOG_FILTER all – * * 0.0.0.0/0 0.0.0.0/0
0 0 LOG tcp – * * 0.0.0.0/0 0.0.0.0/0 tcp flags:0x17/0x02 limit: avg 1/sec burst 5 LOG flags 0 level 6 prefix Inbound ' 0 0 DROP tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp flags:0x17/0x02 0 0 LOG tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp flags:0x17/0x04 limit: avg 1/sec burst 5 LOG flags 0 level 6 prefixInbound '
0 0 DROP tcp – * * 0.0.0.0/0 0.0.0.0/0 tcp flags:0x17/0x04
0 0 LOG icmp – * * 0.0.0.0/0 0.0.0.0/0 icmp type 8 limit: avg 1/sec burst 5 LOG flags 0 level 6 prefix Inbound ' 0 0 DROP icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmp type 8 22 10717 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 limit: avg 5/sec burst 5 LOG flags 0 level 6 prefixInbound '
22 10717 DROP all – * * 0.0.0.0/0 0.0.0.0/0

Chain LSO (0 references)
pkts bytes target prot opt in out source destination
0 0 LOG_FILTER all – * * 0.0.0.0/0 0.0.0.0/0
0 0 LOG all – * * 0.0.0.0/0 0.0.0.0/0 limit: avg 5/sec burst 5 LOG flags 0 level 6 prefix `Outbound '
0 0 REJECT all – * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-port-unreachable

Chain OUTBOUND (3 references)
pkts bytes target prot opt in out source destination
11 1753 ACCEPT icmp – * * 0.0.0.0/0 0.0.0.0/0
1441 241K ACCEPT tcp – * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
15 4911 ACCEPT udp – * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
317 30055 ACCEPT all – * * 0.0.0.0/0 0.0.0.0/0[/code]

i druga…

[code]root@server:/home/administrator# iptables -t nat -nvL
Chain PREROUTING (policy ACCEPT 167 packets, 38924 bytes)
pkts bytes target prot opt in out source destination

Chain POSTROUTING (policy ACCEPT 34 packets, 2770 bytes)
pkts bytes target prot opt in out source destination
242 22140 MASQUERADE all – * eth3 0.0.0.0/0 0.0.0.0/0

Chain OUTPUT (policy ACCEPT 257 packets, 23589 bytes)
pkts bytes target prot opt in out source destination[/code]

Taj Firestarter je poprilicno “glup” . Sta vi tvoj firewall trebao da radi? Blokirati sve incoming ,dozvoliti outgoing ili nesto vise… ?

nije firestarter bio glup u ovom slučaju, nego ja… dakle imam 4 mrežne kartire od čega mi je jedna netxtreme pokvarena… kada sam prebacio na eth0 radilo je…

na žalost ja sam bio glup pa sam prije toga reinstalirao ubuntu, jer sam silno bio frustriran problemom… sada sam vratio firestarter, instalirao dnsmasq, ipmasq. Konekcija je odlična, nema prekida ni na klijentima ni na serveru.

sada samo moram da se sjetim kako sam podesio da mi dhcp prosljeđuje /etc/hosts u lan, tako da kada ukucam http://server uleti na serverov apache.

u /etc/host sam definirao ip 192.168.20.1 pod imenom server, ali klijenti nehaju… morat ću netšto u dnsmasq-u izmijenit…

hvala svima na pomoći i žao mi je što sam vas izmaltretirao.