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nass 08-01-2013 05:56 PM

no internet while downloading torrents - seems dns related
 
Hello everyone,
I have a very peculiar problem regarding the internet connection while downloading torrents.
Before you conclude that I should "reduce the # of half-open & user connections", let me say I have done that.(10 half open connections, 20 users, it still doesn't work , and I don't get any downloading going on anymore).

I should also say that QoS shouldn't be necessary. usually in my experience with downloading torrents (in linux/windows nad mac) the internet connection was shared among all processes. Here it seems like torrents are chewing on all the available bandwidth. (Shouldn't the kernel be divide time among processes that request to send/receive packages?)

Finally, I should say that this problem started appearing after I updated to slack 64bit v14 (from v13.37).

So, the actual problem seems to be related with dns server not responding once I start download with ktorrent or rtorrent. And no webpages load anymore. torrent will be downloading at reasonable speed, but no websites will be loading.
so "nslookup" and "dig" will tell me that the dns server (which btw is located on the same pc) was not found :
Quote:

nslookup facebook.com
;; connection timed out; no servers could be reached
and
Quote:

nass@stargaze:~$ dig !$
dig facebook.com

; <<>> DiG 9.9.1-P3 <<>> facebook.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 26154
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;facebook.com. IN A

;; Query time: 1125 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Fri Aug 2 01:14:46 2013
;; MSG SIZE rcvd: 41
restarting the dns server (bind) while the torrent is running will generally NOT fix things, even though sometimes I have seen this happening.
stopping the dns , deleting any *.jnl files that were generated and restarting seems to work, but again it may not be always.( I don't have a repeated pattern for this case).
I can't say I have found "a way" to get the internet back.
-usually closing ktorrent and waiting for a few secs could even fix the internet on its own.
-Other times closing the ktorrent client and restarting dns server would work faster than the previous case.
-sometimes repeated restarts would NOT get the dns back working (bu waiting for a few mins would fix the prob)
-recently I have started stopping named, deleting *.jnl files and restarting it. This has had 100% success in my (only 2) trials.

the firewall log, the /var/log/messages/ and named's logs, doesn't register anything weird.

I am not keen in the use of tcpdump, wireshark, netstat so I don't know if I can use this tools to identify ...something! Could anyone help with this?

Since this problem seems to be related -primarily- to the dns server, I am appending my dns file and explain my pc's configuration abit.
so ADSL internet arrive in the modem (provided by ISP, always on, even when I dont have internet)
modem is connected to this pc where I am downloading torrents at eth1. this pc is network and file server (and my desktop when I am away). It is running iptables, dns, & squid servers (among others). Then from eth0 of this pc, the wifi and intranet switch is fed.
The squid is running on a transparent configuration but it shouldn't both with torrent traffic as this is done on different ports (rather than the port 80)

So initially I am attaching my named.conf, in an attempt to get feedback on it (perhaps some logically erroneous config that is not caught from the webmin named config file checker - with which I have repeatedly verified that the named.conf file is syntactically correct)

named.conf is here.


If this is fine, is there someway I could start using tcpdump (and any other tool) under your guidance to collect info as to what might be causing this?

Thank you extremely much for your help :)

kfritz 08-01-2013 09:46 PM

Start with:
Code:

tcpdump -ni eth1 port 53
The output is self-explanatory. Try it a few times when you're not BT'ing to get the hang of it. This will show you if you're sending out the DNS queries and when you're getting the replies.

Also, all the BT clients worth their salt have bandwidth limiting options -- try setting them to 1/2 or 3/4 your known bandwidth. I'm guessing that it's just a saturated DSL link. Could be wrong...

nass 08-02-2013 08:07 AM

apparently on a normal
Quote:

ssh nass@domain.name -p 34567
when I have no problems with connectivity

the command :
Quote:

tcpdump -i eth1 -s 128 port 53
Quote:

15:56:53.694228 IP 192.168.231.165.12433 > dns2.tellas.gr.domain: 25375+ [1au] AAAA? domain.name. (42)
15:56:53.715447 IP dns2.tellas.gr.domain > 192.168.231.165.12433: 25375 Refused- 0/0/1 (42)
15:56:53.715728 IP 192.168.231.165.9430 > dns1.tellas.gr.domain: 61082+ [1au] AAAA? domain.name. (42)
15:56:53.737400 IP dns1.tellas.gr.domain > 192.168.231.165.9430: 61082 Refused- 0/0/1 (42)
15:56:53.737647 IP 192.168.231.165.57958 > resolver2.opendns.com.domain: 21923+ [1au] AAAA? domain.name. (42)
15:56:54.214879 IP resolver2.opendns.com.domain > 192.168.231.165.57958: 21923 0/0/1 (42)
15:56:54.215532 IP 192.168.231.165.18726 > dns2.tellas.gr.domain: 27041+ [1au] AAAA? domain.name. (42)
15:56:54.237547 IP dns2.tellas.gr.domain > 192.168.231.165.18726: 27041 Refused- 0/0/1 (42)
15:56:54.237816 IP 192.168.231.165.22739 > dns1.tellas.gr.domain: 23657+ [1au] AAAA? domain.name. (42)
15:56:54.259972 IP dns1.tellas.gr.domain > 192.168.231.165.22739: 23657 Refused- 0/0/1 (42)
15:56:54.260239 IP 192.168.231.165.63128 > resolver2.opendns.com.domain: 40910+ [1au] AAAA? domain.name. (42)
15:56:54.343751 IP resolver2.opendns.com.domain > 192.168.231.165.63128: 40910 0/1/1 (125)
15:56:54.344364 IP 192.168.231.165.39746 > dns2.tellas.gr.domain: 6064+ [1au] A? domain.name. (42)
15:56:54.365646 IP dns2.tellas.gr.domain > 192.168.231.165.39746: 6064 Refused- 0/0/1 (42)
15:56:54.365927 IP 192.168.231.165.8377 > dns1.tellas.gr.domain: 56007+ [1au] A? domain.name. (42)
15:56:54.387803 IP dns1.tellas.gr.domain > 192.168.231.165.8377: 56007 Refused- 0/0/1 (42)
15:56:54.388064 IP 192.168.231.165.40752 > resolver2.opendns.com.domain: 24391+ [1au] A? domain.name. (42)
15:56:54.850802 IP resolver2.opendns.com.domain > 192.168.231.165.40752: 24391 1/0/1 A <got an ip address> (58)
^C
So correct me if I don't read this properly, but most of the forwarders I have , refuse to give me an answer
Quote:

15:56:53.715447 IP dns2.tellas.gr.domain > 192.168.231.165.12433: 25375 Refused- 0/0/1 (42)
they only seem to send me their authority record?
Other forwarders reply something I don;t understand.
Quote:

15:56:54.214879 IP resolver2.opendns.com.domain > 192.168.231.165.57958: 21923 0/0/1 (42)
?

Finally , I get an answer in the end, but it is weird that most server refuse to reply... Why is that?

nass 08-02-2013 09:44 AM

also, when I start downloading a torrent
and I try too ssh to another domain (to avoid any caching problems), I get back the following


Quote:

17:05:31.412905 IP 192.168.231.165.26627 > dns2.tellas.gr.domain: 65406+ [1au] AAAA? another.domain. (46)
17:05:31.413013 IP 192.168.231.165.1088 > dns2.tellas.gr.domain: 5768+ [1au] NS? . (28)
17:05:33.413110 IP 192.168.231.165.23237 > dns1.tellas.gr.domain: 9078+ [1au] AAAA? another.domain. (46)
17:05:33.413125 IP 192.168.231.165.5737 > dns1.tellas.gr.domain: 25346+ [1au] NS? . (28)
17:05:35.413226 IP 192.168.231.165.7364 > google-public-dns-b.google.com.domain: 13879+ [1au] AAAA? another.domain. (46)
17:05:35.413246 IP 192.168.231.165.35628 > google-public-dns-b.google.com.domain: 52495+ [1au] NS? . (28)
17:05:37.413338 IP 192.168.231.165.39465 > resolver2.opendns.com.domain: 50305+ [1au] NS? . (28)
17:05:37.413377 IP 192.168.231.165.31973 > resolver2.opendns.com.domain: 57962+ [1au] AAAA? another.domain. (46)
17:05:39.413473 IP 192.168.231.165.16392 > google-public-dns-a.google.com.domain: 42375+ [1au] AAAA? another.domain. (46)
17:05:39.413507 IP 192.168.231.165.15032 > google-public-dns-a.google.com.domain: 51846+ [1au] NS? . (28)
17:05:41.413543 IP 192.168.231.165.28097 > resolver1.opendns.com.domain: 42881+ [1au] AAAA? another.domain. (46)
17:05:41.413582 IP 192.168.231.165.51338 > resolver1.opendns.com.domain: 17660+ [1au] NS? . (28)
17:05:43.413697 IP 192.168.231.165.59098 > 198.41.0.4.domain: 25654 AAAA? another.domain. (35)
17:05:43.413725 IP 192.168.231.165.48732 > 198.41.0.4.domain: 21403 NS? . (17)
17:05:43.414192 IP 192.168.231.165.61874 > dns2.tellas.gr.domain: 39746+ [1au] PTR? 4.0.41.198.in-addr.arpa. (52)
17:05:44.213828 IP 192.168.231.165.14526 > b.root-servers.net.domain: 36487 NS? . (17)
17:05:44.213849 IP 192.168.231.165.49809 > b.root-servers.net.domain: 3885 AAAA? another.domain. (35)
17:05:45.013924 IP 192.168.231.165.53800 > 192.33.4.12.domain: 38970 AAAA? another.domain. (35)
17:05:45.013944 IP 192.168.231.165.15246 > 192.33.4.12.domain: 29411 NS? . (17)
17:05:45.414446 IP 192.168.231.165.9403 > dns1.tellas.gr.domain: 64198+ [1au] PTR? 4.0.41.198.in-addr.arpa. (52)
17:05:45.814132 IP 192.168.231.165.17854 > 128.8.10.90.domain: 13817 NS? . (17)
17:05:45.814160 IP 192.168.231.165.38234 > 128.8.10.90.domain: 6103 AAAA? another.domain. (35)
17:05:46.614274 IP 192.168.231.165.59079 > 192.203.230.10.domain: 58541 AAAA? another.domain. (35)
so I seem to be sending out some "NS?" but no replies.
I also seem to reach out to some b.root-servers (with ip "192.33.4.12")
and do be getting some suggestions to ask a.root-servers "PTR? 4.0.41.198.in-addr.arpa.". This is weird. Weren't the tellas.gr DNS servers refusing to reply to be when I wasn't downloading torrents in my previous post?!

kfritz 08-02-2013 11:34 AM

You seem to have 2 problems. The first is a misconfigured bind daemon. Can't help there, I'm blissfully ignorant of bind configs -- but if you're getting refused, you're not pointing to the right servers for the names you're resolving. But that's not your main problem.

Assuming that you're downloading, not uploading, then some upstream router is discarding UDP in favor of TCP, and you're not seeing the replies. If you're seeding as well, then the request could be discarded as well.

Try a traceroute to some of your DNS servers before and during BT. Traceroute uses UDP by default and should suffer the same results, and if so you should be able to figure out which router is dropping UDP. Make sure you use -n option while BT is running, otherwise it will be trying to resolve the IP's to names using DNS.

mRgOBLIN 08-03-2013 01:26 AM

As kfritz has already pointed out.... Seems an awful lot like a saturated uplink. Have you tried setting your upload speed to something very low 5-10Kb?

nass 08-04-2013 05:27 PM

I did try to reduce UL to 5kb and it seems to work now, but to really make sure i won't lose connectivity for surfing, i had to impose a limit on the download rate as well (400kbps, for my 5.6Mbps speedtest - connection).

BUT:
i am at a location with far slower internet connection right now. with another pc, and downloading a torrent. How do you explain that without an intervention (limiting UL/DL) on my part, i can download torrents AND be able to surf in the meantime?

This i can not comprehend.


kfritz the refusals where related to the fact that my ISP had changed its dns servers. updated and running fine now.

nass 08-05-2013 07:08 PM

hm... its weird, now I noticed I randomly lose internet connectivity at random times, without even downloading anything.
using tcpdump as instructed by kfritz, i see that while i cannot surf the net, dns server gets no replies once again (as in post #4 , above).

iptraf shows that the average rates are reasonable (10 - 30kbps, i am not downloading anything).
I am puzzled and I do not know how to proceed....

wildwizard 08-06-2013 04:14 AM

I don't know tcpdump well but I do know dig very well.

Checking your tellas.gr dns servers and they respond with :-
Code:

; <<>> DiG 9.9.2-P2 <<>> @dns2.tellas.gr
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: REFUSED, id: 34709
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; WARNING: recursion requested but not available

The last line in particular is important as it tell us that the server is only good for resolving names that it is responsible for and nothing else.

If you have these servers listed as forwarders in your bind config you need to remove them.

Another handy feature of dig is the +trace option as it will show each step of the name resolution so you can see which server is causing you issues.

nass 08-06-2013 07:37 AM

Quote:

Another handy feature of dig is the +trace option as it will show each step of the name resolution so you can see which server is causing you issues.
this is nice, i'll try it on every dns server in my forwarders list.

Also what dig command did you use above?

If i try :
Quote:

nass@stardust:~$ dig -x 62.169.194.47

; <<>> DiG 9.8.1-P1 <<>> -x 62.169.194.47
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 7874
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2

;; QUESTION SECTION:
;47.194.169.62.in-addr.arpa. IN PTR

;; ANSWER SECTION:
47.194.169.62.in-addr.arpa. 86400 IN PTR dns3.tellas.gr.

;; AUTHORITY SECTION:
194.169.62.in-addr.arpa. 86391 IN NS dns1.tellas.gr.
194.169.62.in-addr.arpa. 86391 IN NS dns2.tellas.gr.

;; ADDITIONAL SECTION:
dns1.tellas.gr. 291 IN A 62.169.194.17
dns2.tellas.gr. 291 IN A 62.169.194.18

;; Query time: 4 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Tue Aug 6 15:30:53 2013
;; MSG SIZE rcvd: 142
I have setup my forwarders to use dns3, cause dns2 and dns1 where giving me refusals (see post above)

I am at the office now so outside my ISPs boundaries, digging dns[321] gives "NOERROR":

Quote:

nass@stardust:~$ dig dns3.tellas.gr

; <<>> DiG 9.8.1-P1 <<>> dns3.tellas.gr
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 21136
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2

;; QUESTION SECTION:
;dns3.tellas.gr. IN A

;; ANSWER SECTION:
dns3.tellas.gr. 300 IN A 62.169.194.47

;; AUTHORITY SECTION:
tellas.gr. 26 IN NS dns1.tellas.gr.
tellas.gr. 26 IN NS dns2.tellas.gr.

;; ADDITIONAL SECTION:
dns1.tellas.gr. 26 IN A 62.169.194.17
dns2.tellas.gr. 26 IN A 62.169.194.18

;; Query time: 4 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Tue Aug 6 15:35:17 2013
;; MSG SIZE rcvd: 118

nass@stardust:~$ dig dns2.tellas.gr

; <<>> DiG 9.8.1-P1 <<>> dns2.tellas.gr
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 62575
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1

;; QUESTION SECTION:
;dns2.tellas.gr. IN A

;; ANSWER SECTION:
dns2.tellas.gr. 16 IN A 62.169.194.18

;; AUTHORITY SECTION:
tellas.gr. 16 IN NS dns2.tellas.gr.
tellas.gr. 16 IN NS dns1.tellas.gr.

;; ADDITIONAL SECTION:
dns1.tellas.gr. 16 IN A 62.169.194.17

;; Query time: 3 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Tue Aug 6 15:35:27 2013
;; MSG SIZE rcvd: 97

nass@stardust:~$ dig dns1.tellas.gr

; <<>> DiG 9.8.1-P1 <<>> dns1.tellas.gr
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 45790
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1

;; QUESTION SECTION:
;dns1.tellas.gr. IN A

;; ANSWER SECTION:
dns1.tellas.gr. 12 IN A 62.169.194.17

;; AUTHORITY SECTION:
tellas.gr. 12 IN NS dns1.tellas.gr.
tellas.gr. 12 IN NS dns2.tellas.gr.

;; ADDITIONAL SECTION:
dns2.tellas.gr. 12 IN A 62.169.194.18

;; Query time: 3 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Tue Aug 6 15:35:32 2013
;; MSG SIZE rcvd: 97
if I ssh into my home and do the same
Quote:

nass@stargaze:~$ dig dns3.tellas.gr

; <<>> DiG 9.9.1-P3 <<>> dns3.tellas.gr
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 11318
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 8, ADDITIONAL: 11

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;dns3.tellas.gr. IN A

;; ANSWER SECTION:
dns3.tellas.gr. 300 IN A 62.169.194.47

;; AUTHORITY SECTION:
gr. 154132 IN NS gr-at.ics.forth.gr.
gr. 154132 IN NS grdns.ics.forth.gr.
gr. 154132 IN NS gr-us.ics.forth.gr.
gr. 154132 IN NS gr-m.ics.forth.gr.
gr. 154132 IN NS gr-br.ics.forth.gr.
gr. 154132 IN NS grdns-de.denic.de.
gr. 154132 IN NS gr-ix.ics.forth.gr.
gr. 154132 IN NS estia.ics.forth.gr.

;; ADDITIONAL SECTION:
gr-m.ics.forth.gr. 2966 IN AAAA 2001:678:7::4:10
estia.ics.forth.gr. 334 IN AAAA 2001:648:2c30::191:3
gr-at.ics.forth.gr. 3069 IN A 78.104.145.227
gr-br.ics.forth.gr. 172180 IN A 200.160.7.163
gr-ix.ics.forth.gr. 2207 IN A 176.126.38.132
gr-ix.ics.forth.gr. 3851 IN AAAA 2001:7f8:6e:1::132
gr-us.ics.forth.gr. 172180 IN A 199.4.28.219
gr-us.ics.forth.gr. 172180 IN AAAA 2620:0:22b0:4:221:9bff:fe97:dc44
grdns.ics.forth.gr. 3776 IN A 139.91.1.1
grdns-de.denic.de. 2907 IN A 81.91.161.80

;; Query time: 128 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Tue Aug 6 15:36:58 2013
;; MSG SIZE rcvd: 447

nass@stargaze:~$ dig dns2.tellas.gr

; <<>> DiG 9.9.1-P3 <<>> dns2.tellas.gr
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 37706
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 8, ADDITIONAL: 11

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;dns2.tellas.gr. IN A

;; ANSWER SECTION:
dns2.tellas.gr. 212 IN A 62.169.194.18

;; AUTHORITY SECTION:
gr. 154118 IN NS gr-at.ics.forth.gr.
gr. 154118 IN NS gr-ix.ics.forth.gr.
gr. 154118 IN NS gr-m.ics.forth.gr.
gr. 154118 IN NS grdns.ics.forth.gr.
gr. 154118 IN NS gr-br.ics.forth.gr.
gr. 154118 IN NS estia.ics.forth.gr.
gr. 154118 IN NS gr-us.ics.forth.gr.
gr. 154118 IN NS grdns-de.denic.de.

;; ADDITIONAL SECTION:
gr-m.ics.forth.gr. 2952 IN AAAA 2001:678:7::4:10
estia.ics.forth.gr. 320 IN AAAA 2001:648:2c30::191:3
gr-at.ics.forth.gr. 3055 IN A 78.104.145.227
gr-br.ics.forth.gr. 172166 IN A 200.160.7.163
gr-ix.ics.forth.gr. 2193 IN A 176.126.38.132
gr-ix.ics.forth.gr. 3837 IN AAAA 2001:7f8:6e:1::132
gr-us.ics.forth.gr. 172166 IN A 199.4.28.219
gr-us.ics.forth.gr. 172166 IN AAAA 2620:0:22b0:4:221:9bff:fe97:dc44
grdns.ics.forth.gr. 3762 IN A 139.91.1.1
grdns-de.denic.de. 2893 IN A 81.91.161.80

;; Query time: 69 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Tue Aug 6 15:37:13 2013
;; MSG SIZE rcvd: 447

nass@stargaze:~$ dig dns1.tellas.gr

; <<>> DiG 9.9.1-P3 <<>> dns1.tellas.gr
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 28999
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 8, ADDITIONAL: 11

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;dns1.tellas.gr. IN A

;; ANSWER SECTION:
dns1.tellas.gr. 24 IN A 62.169.194.17

;; AUTHORITY SECTION:
gr. 154113 IN NS grdns.ics.forth.gr.
gr. 154113 IN NS gr-us.ics.forth.gr.
gr. 154113 IN NS gr-br.ics.forth.gr.
gr. 154113 IN NS gr-ix.ics.forth.gr.
gr. 154113 IN NS gr-at.ics.forth.gr.
gr. 154113 IN NS gr-m.ics.forth.gr.
gr. 154113 IN NS grdns-de.denic.de.
gr. 154113 IN NS estia.ics.forth.gr.

;; ADDITIONAL SECTION:
gr-m.ics.forth.gr. 2947 IN AAAA 2001:678:7::4:10
estia.ics.forth.gr. 315 IN AAAA 2001:648:2c30::191:3
gr-at.ics.forth.gr. 3050 IN A 78.104.145.227
gr-br.ics.forth.gr. 172161 IN A 200.160.7.163
gr-ix.ics.forth.gr. 2188 IN A 176.126.38.132
gr-ix.ics.forth.gr. 3832 IN AAAA 2001:7f8:6e:1::132
gr-us.ics.forth.gr. 172161 IN A 199.4.28.219
gr-us.ics.forth.gr. 172161 IN AAAA 2620:0:22b0:4:221:9bff:fe97:dc44
grdns.ics.forth.gr. 3757 IN A 139.91.1.1
grdns-de.denic.de. 2888 IN A 81.91.161.80

;; Query time: 65 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Tue Aug 6 15:37:18 2013
;; MSG SIZE rcvd: 447
That is weird. no refusals now....

wildwizard 08-07-2013 03:16 AM

The last bunch of queries you have are for the domain tellas.gr itself so your queries will work as there is no recursive look-up required.

If you use
Code:

dig @dns1.tellas.gr www.google.com
Then you will query dns1.tellas.gr directly for the address of www.google.com

I got no response from dns3/dns4.tellas.gr so I would assume these servers are internal to your ISP's network and are the ones you should be using as a customer.

dns1/dns2 would be the servers presented to the outside that host the ISP's domain and are not for general use, ie they only resolve the ISP's domain and nothing else.


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