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DNS Issues Technicolor TG582n

NivagSwerdna
Dabbler
Posts: 20
Registered: 05-08-2013

DNS Issues Technicolor TG582n

Out of the blue I have lost connectivity from all the devices on my LAN
It appears that DNS names are not resolving.
Currently all the LAN devices use DHCP to return a DNS Server address of 192.168.1.1 (the router)
The router then acts as a DNS relay to
Primary DNS: 212.159.6.9
Secondary DNS: 212.159.6.10
However DNS names are not resolving anymore.
If I change a PC to have 192.168.1.1 & 212.159.6.10 it does seem to (at least sometimes) resolve DNS
What has changed to break the DNS relay function of my PlusNet supplied routerHuh
Thanks in advance
Nivag
22 REPLIES
NivagSwerdna
Dabbler
Posts: 20
Registered: 05-08-2013

Re: DNS Issues Technicolor TG582n

nslookup www.yahoo.com 192.168.1.1
Server:  UnKnown
Address:  192.168.1.1
DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
*** Request to UnKnown timed-out
Very odd.
nslookup www.yahoo.com 212.159.6.10
Server:  cdns02.plus.net
Address:  212.159.6.10
Non-authoritative answer:
Name:    ds-eu-fp3.wa1.b.yahoo.com
Addresses:  2a00:1288:f006:1fe::3000
          2a00:1288:f00e:1fe::3001
          2a00:1288:f006:1fe::3001
          2a00:1288:f00e:1fe::3000
          46.228.47.115
          46.228.47.114
Aliases:  www.yahoo.com
          fd-fp3.wg1.b.yahoo.com
          ds-fp3.wg1.b.yahoo.com
          ds-eu-fp3-lfb.wa1.b.yahoo.com

Router looks fine...
Connection Information

Uptime: 0 days, 0:49:46
Data Transferred (Sent/Received) [MB/GB]: 187.75 / 7.66
Username: XXXXXX@plusdsl.net
Password: ********
Remember Password: Yes
IP Address: AAA.BBB.CCC.DDD
Primary DNS: 212.159.6.9
Secondary DNS: 212.159.6.10
Looks OK
Just DNS via 192.168.1.1 that is broken
NivagSwerdna
Dabbler
Posts: 20
Registered: 05-08-2013

Re: DNS Issues Technicolor TG582n

Interesting... appears intermittent....
nslookup www.yahoo.com 192.168.1.1
Server:  UnKnown
Address:  192.168.1.1
Non-authoritative answer:
Name:    ds-eu-fp3.wa1.b.yahoo.com
Addresses:  2a00:1288:f006:1fe::3001
          2a00:1288:f00e:1fe::3000
          2a00:1288:f00e:1fe::3001
          2a00:1288:f006:1fe::3000
          46.228.47.114
          46.228.47.115
Aliases:  www.yahoo.com
          fd-fp3.wg1.b.yahoo.com
          ds-fp3.wg1.b.yahoo.com
          ds-eu-fp3-lfb.wa1.b.yahoo.com

Are there system wide DNS issues at presentHuh
Community Veteran
Posts: 5,057
Thanks: 424
Fixes: 16
Registered: 10-06-2010

Re: DNS Issues Technicolor TG582n

A handful of people have previously reported problems with the DNS forwarding server in the router:
https://community.plus.net/forum/index.php/topic,122856.msg1083269.html#msg1083269
https://community.plus.net/forum/index.php/topic,116178.0.html
I don't think anyone knows the exact cause of the problem or if 212.159.6.9 being slow to respond, or packets being lost to the way to/from 212.159.6.9 might have anything to do with the problem.
It is possible to configure the router's DHCP server to assign different DNS server addresses to devices on your network: http://npr.me.uk/changedns.html "Method 2" to workaround the problem.
Community Veteran
Posts: 2,274
Thanks: 109
Fixes: 4
Registered: 18-02-2013

Re: DNS Issues Technicolor TG582n

A quick look at DNS-Servers in general for today. Everything appears to be in order.
The dozen or so popular servers i've tested below seem fine today, the test below sends 10 requests to google.com and uses 5 of those requests to give the results you see below for each server.
[tt]Nameserver          Response Time (ms)
                    min/avg/max/stdev/retries
192.168.0.15        0.55/0.56/0.56/0.00/0
192.168.0.254      19.41/19.88/20.27/0.29/0
212.159.6.9        19.32/19.51/19.60/0.10/0
212.159.6.10        18.57/19.51/20.79/0.86/0
212.159.13.49      18.51/19.34/20.24/0.62/0
212.159.13.50      18.35/19.22/19.98/0.68/0
208.67.222.222      17.98/18.27/18.43/0.17/0
208.67.222.220      17.96/18.41/18.78/0.26/0
208.67.222.123      18.19/18.37/18.66/0.17/0
208.67.220.123      17.94/18.27/18.69/0.26/0
8.8.8.8            23.23/24.04/25.18/0.69/0
8.8.4.4            17.53/17.89/18.28/0.31/0
4.2.2.1            17.68/18.17/18.73/0.44/0
4.2.2.6            17.69/18.23/18.58/0.30/0

The following name servers are used for lookup of google.co.uk.
forwarding request:
Delegation with 0 names, of which 0 can be examined to query further addresses.
It provides 2 IP addresses.
208.67.222.123  rto 53 msec, ttl 116, ping 25 var 7 rtt 53, tA 0, tAAAA 0, tother 0, EDNS 0 probed.
208.67.220.123  rto 44 msec, ttl 192, ping 24 var 5 rtt 50, tA 0, tAAAA 0, tother 0, EDNS 0 probed.[/tt]
The test above is just giving me a gerneral thumbs up that all is well with my normal Opendns servers that i use via my cache.

And the 2 tests below are samples taken in the last hour, they also test the 20 or so dns-servers with about 200 global requests each.
As you can see Level3 has a few requests failing, but nothing major in all honesty.
ejs has pointed out that a few people have had problems with the TG582N forwarder, but nothing conclusive has been proved. One way of solving your problem NivagSwerdna is by disabling the forwarder as ejs has pointed out, although that option does work, it doesn't work for me because i need to force the route for dns traffic through the forwarder. IE  for Opendns.

NivagSwerdna
Dabbler
Posts: 20
Registered: 05-08-2013

Re: DNS Issues Technicolor TG582n

I really want to keep the DNS relay function in the Technicolor as I also have a habit of adding my own static entries and would like to continue to not have to define my own bind/DNS service...
Anyway...
Got home today to loads of grumbles from the family... nothing accessible again... DNS resolution down again...
Once again....

nslookup www.yahoo.com 192.168.1.1
Server:  UnKnown
Address:  192.168.1.1
DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
*** Request to UnKnown timed-out
but
nslookup www.yahoo.com 212.159.6.9
Server:  cdns01.plus.net
Address:  212.159.6.9
Non-authoritative answer:
Name:    ds-eu-fp3.wa1.b.yahoo.com
Addresses:  2a00:1288:f00e:1fe::3000
          2a00:1288:f006:1fe::3000
          2a00:1288:f00e:1fe::3001
          2a00:1288:f006:1fe::3001
          46.228.47.115
          46.228.47.114
Aliases:  www.yahoo.com
          fd-fp3.wg1.b.yahoo.com
          ds-fp3.wg1.b.yahoo.com
          ds-eu-fp3-lfb.wa1.b.yahoo.com
Clearly the DNS relay in the technicolor (stock Plusnet router) stuffed again.
Decided to have a closer look...
{admin}[dns server route]=>list
DNS Server Entries:
  DNS Server    Source                Label              Metric Intf        State  Domain
D 212.159.6.9                                            10    Internet      UP      *
D 212.159.6.10                                            10    Internet      UP      *
Not sure what the "D" on the front of the line means but it doesn't look healthy
{admin}[dns server route]=>flush
{admin}[dns server route]=>add dns=212.159.6.10 metric=0 intf=Internet
{admin}[dns server route]=>add dns=212.159.6.9 metric=0 intf=Internet
{admin}[dns server route]=>list
DNS Server Entries:
  DNS Server    Source                Label              Metric Intf        State  Domain
S 212.159.6.10                                            0      Internet      UP      *
S 212.159.6.9                                            0      Internet      UP      *
{admin}[dns server route]=>
And then back to the PC...
nslookup www.yahoo.com 192.168.1.1
Server:  UnKnown
Address:  192.168.1.1
Non-authoritative answer:
Name:    ds-eu-fp3.wa1.b.yahoo.com
Addresses:  2a00:1288:f006:1fe::3000
          2a00:1288:f006:1fe::3001
          2a00:1288:f00e:1fe::3000
          2a00:1288:f00e:1fe::3001
          46.228.47.114
          46.228.47.115
          77.238.160.51
Aliases:  www.yahoo.com
          fd-fp3.wg1.b.yahoo.com
          ds-fp3.wg1.b.yahoo.com
          ds-eu-fp3-lfb.wa1.b.yahoo.com

Working again for now.  I don't imagine I'm the only person suffering this.  What has changed?
Community Veteran
Posts: 1,840
Thanks: 101
Fixes: 6
Registered: 21-01-2013

Re: DNS Issues Technicolor TG582n

What result do you get from the following cli command?
dhcp server pool list name=LAN_private
NivagSwerdna
Dabbler
Posts: 20
Registered: 05-08-2013

Re: DNS Issues Technicolor TG582n

Go and have a bath.... listening to BBC Radio Player, HHGTG Fit The First, in the bath....  Smiley
20 mins in... silence...
Come down stairs to find....

nslookup www.yahoo.com 192.168.1.1
Server:  UnKnown
Address:  192.168.1.1
DNS request timed out.
   timeout was 2 seconds.
DNS request timed out.
   timeout was 2 seconds.
DNS request timed out.
   timeout was 2 seconds.
DNS request timed out.
   timeout was 2 seconds.
*** Request to UnKnown timed-out



{admin}[dns server route]=>list
DNS Server Entries:
 DNS Server     Source                Label              Metric Intf         State  Domain
S 212.159.6.10                                            0      Internet      UP      *
S 212.159.6.9                                             0      Internet      UP      *

So router appears normal... And has not dropped (Uptime: 0 days, 3:58:59)
Did

{admin}[dns server route]=>flush
{admin}[dns server route]=>add dns=212.159.6.10 metric=0 intf=Internet
{admin}[dns server route]=>add dns=212.159.6.9 metric=0 intf=Internet
{admin}[dns server route]=>list
DNS Server Entries:
 DNS Server     Source                Label              Metric Intf         State  Domain
S 212.159.6.10                                            0      Internet      UP      *
S 212.159.6.9                                             0      Internet      UP      *
{admin}[dns server route]=>

And temporarily working again.  Something causing the Technicolor Router DNS to go deaf.
There are some disconcerting things in the logs....

Mar 14 20:30:18 IDS scan parser : tcp port scan: 173.194.41.161 scanned at least 10 ports at A.B.C.D. (1 of 1) : 173.194.41.161 A.B.C.D 0040 TCP 443->55150 [...R..] seq 1069446595 win 0
and lots of...
Mar 14 18:16:14 FIREWALL replay check (1 of 1): Protocol: ICMP Src ip: 178.44.133.228 Dst ip:  A.B.C.D Type: Destination Unreachable Code: Port Unreacheable
NivagSwerdna
Dabbler
Posts: 20
Registered: 05-08-2013

Re: DNS Issues Technicolor TG582n

{admin}=>dhcp server pool list name=LAN_private
Pool              Address Range        Intf      Admin  Alloc  State
0  LAN_private    192.168.1.[201-252]  LocalNetwork up    dynamic static
DHCP server  = 192.168.1.1
Netmask      = 255.255.255.0
Leasetime    = 86400s
Lockouttime  = 180s
Gateway      = 192.168.1.1
DNS domain    = myDomain.com
DNS address list:
192.168.1.1 (local DNS)
{admin}=>

Looks fine
NivagSwerdna
Dabbler
Posts: 20
Registered: 05-08-2013

Re: DNS Issues Technicolor TG582n

This is interesting....
{admin}[dns server debug]=>stats
Corrupted packets received      :    30075
Local questions resolved        :        0
Local negative answers sent      :      312
Total DNS packets forwarded      :    32591
External answers received        :      4240
Spoofed responses                :      212
Forward table full, discard      :        98
Spurious answers                :      954
Unknown query types              :        0

I'll reset stats and see if these are current.
Community Veteran
Posts: 1,840
Thanks: 101
Fixes: 6
Registered: 21-01-2013

Re: DNS Issues Technicolor TG582n

Don't know if this is the cause of your problem but I'm not sure "myDomain.com" is a good idea.
Anything ending with a 1st level domain seems a bad idea to me.
Try reverting to "lan" or just "mydomain"
NivagSwerdna
Dabbler
Posts: 20
Registered: 05-08-2013

Re: DNS Issues Technicolor TG582n

Gone deaf again.  I wonder what a 'corrupted packet' is?  Some sort of DoS attack?
{admin}[dns server debug]=>stats
Corrupted packets received      :    10672
Local questions resolved        :        0
Local negative answers sent      :        6
Total DNS packets forwarded      :      9544
External answers received        :      1968
Spoofed responses                :        39
Forward table full, discard      :        11
Spurious answers                :        58
Unknown query types              :        0
{admin}[dns server debug]=>

NivagSwerdna
Dabbler
Posts: 20
Registered: 05-08-2013

Re: DNS Issues Technicolor TG582n

Also the "dns server spoof list" seems to have many entries... no idea what that means!
NivagSwerdna
Dabbler
Posts: 20
Registered: 05-08-2013

Re: DNS Issues Technicolor TG582n

There seems to be nothing I can do to keep my DNS relay alive...
{admin}[dns server debug]=>stats
Corrupted packets received      :    46177
Local questions resolved        :        0
Local negative answers sent      :      104
Total DNS packets forwarded      :      4670
External answers received        :      6459
Spoofed responses                :        42
Forward table full, discard      :      989
Spurious answers                :      1385
Unknown query types              :        0
{admin}[dns server debug]=>

So giving up on the Technicolor for a few days and just hardcoding 212.159.6.9 as DNS server
Something isn't right at all.... Maybe someone is spoofing DNS?
Community Veteran
Posts: 2,274
Thanks: 109
Fixes: 4
Registered: 18-02-2013

Re: DNS Issues Technicolor TG582n

{admin}=>:connection list proto=udp
{admin}=>:connection list ip=192.168.1.1