Plusnet secondary DNS is not responding

[#1]

1st, I've seen:

Plusnet-gateway-and-DNS-problems 

Read some of it, feels like a different issue. (hnec new thread)

Various devices have been reporting that lack internet access, phones have switched to 4G (costing real money BTW)

I have a fairly convoluted setup , but end up on a Vigor 2680 , on the page Online status physical connection it shows two plusnet DNS servers:

Primary: 212.159.6.9

Secondary: 212.159.6.10

The Secondary is not responding (from inside nslookup(1) (sorry, old skol):

> server 212.159.6.9
Default server: 212.159.6.9
Address: 212.159.6.9#53
> google.com
Server: 212.159.6.9
Address: 212.159.6.9#53

Non-authoritative answer:
Name: google.com
Address: 142.250.178.14
> server 212.159.6.10
Default server: 212.159.6.10
Address: 212.159.6.10#53
> google.com
;; connection timed out; no servers could be reached
>

As I say I have a convoluted setup, so this will get resolved for normal clients albeit with a large delay on 1st use of a name.

(FYI: I'm going to switch to 1.1.1.1  , to avoid the plunet issue)

[#2]

Hi @graemev

I just tried nslookup several times against 212.159.6.10 on one of RPi's.
No problems seen.

User@xxxx:~ $ nslookup www.google.com 212.159.6.10
Server: 212.159.6.10
Address: 212.159.6.10#53

Non-authoritative answer:
Name: www.google.com
Address: 142.250.200.36
Name: www.google.com
Address: 2a00:1450:4009:821::2004

Regards
Richard

[#3]

Hi @graemev 

I concur with @RichardB I'm not seeing any issues either and we've no other reports of this nature as far as I'm aware. 

Can you try simplifying your setup and use the Plusnet router to narrow things down?

[@Gandalf]

Hi @Gandalf

Sorry can't use the the Plusnet router . Tried it when I switched to Fibre but it can't set static routes , so it's never worked on my network ...I think gave it to a friend who used Plusnet at the time.

However, today the situation has changed . This had (probably) been going on for months, curious it changed at that point ....I guess I could try rolling back MY changes , to see if changed happened elsewhere but they shouldn't be affecting the nslookup(1) as it goes direct:

graeme@zbox:~$ nslookup
> server 212.159.6.9
Default server: 212.159.6.9
Address: 212.159.6.9#53
> google.com
Server: 212.159.6.9
Address: 212.159.6.9#53

Non-authoritative answer:
Name: google.com
Address: 142.250.187.206
> server 212.159.6.10
Default server: 212.159.6.10
Address: 212.159.6.10#53
> google.com
Server: 212.159.6.10
Address: 212.159.6.10#53

Non-authoritative answer:
Name: google.com
Address: 216.58.212.238
> server
Default server: 212.159.6.10
Address: 212.159.6.10#53

Pretty sure it's just going directly to the one IP address, but to be sure traced it and port 53 is only mentioned twice:

[pid 31122] sendmsg(20, {msg_name={sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("212.159.6.9")}, msg_namelen=16, msg_iov=[{iov_base="G\0\1\0\0\1\0\0\0\0\0\0\6google\3com\0\0\1\0\1", iov_len=28}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, $
[pid 31124] <... epoll_wait resumed> [{EPOLLIN, {u32=3, u64=3}}], 64, -1) = 1
[pid 31122] <... sendmsg resumed> ) = 28
[pid 31124] read(3, <unfinished ...>
[pid 31122] futex(0x7f30737830a4, FUTEX_WAIT_PRIVATE, 3, NULL <unfinished ...>
[pid 31124] <... read resumed> "\24\0\0\0\375\377\377\377", = 8
[pid 31124] epoll_ctl(5, EPOLL_CTL_ADD, 20, {EPOLLIN, {u32=20, u64=20}}) = 0
[pid 31124] read(3, 0x7f306c344e48, = -1 EAGAIN (Resource temporarily unavailable)
[pid 31124] epoll_wait(5, [{EPOLLIN, {u32=20, u64=20}}], 64, -1) = 1
[pid 31124] futex(0x7f30737830a4, FUTEX_WAKE_OP_PRIVATE, 1, 1, 0x7f30737830a0, FUTEX_OP_SET<<28|0<<12|FUTEX_OP_CMP_GT<<24|0x1) = 1
[pid 31122] <... futex resumed> ) = 0
[pid 31124] epoll_ctl(5, EPOLL_CTL_DEL, 20, 0x7f306c344e38 <unfinished ...>
[pid 31122] futex(0x7f3073783028, FUTEX_WAKE_PRIVATE, 1 <unfinished ...>
[pid 31124] <... epoll_ctl resumed> ) = 0
[pid 31122] <... futex resumed> ) = 0
[pid 31124] epoll_wait(5, <unfinished ...>
[pid 31122] recvmsg(20, {msg_name={sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("212.159.6.9")}, msg_namelen=128->16, msg_iov=[{iov_base="G\0\201\200\0\1\0\1\0\0\0\0\6google\3com\0\0\1\0\1\300\f\0\1"..., iov_len=65535}], msg_iovlen=1, msg_con$
[pid 31122] fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 1), ...}) = 0
[pid 31122] mprotect(0x7f306402c000, 4096, PROT_READ|PROT_WRITE) = 0
[pid 31122] write(1, "Server:\t\t212.159.6.9\n", 21Server: 212.159.6.9
) = 21
[pid 31122] write(1, "Address:\t212.159.6.9#53\n", 24Address: 212.159.6.9#53
) = 24
[pid 31122] write(1, "\n", 1
) = 1
[pid 31122] write(1, "Non-authoritative answer:\n", 26Non-authoritative answer:
) = 26
[pid 31122] write(1, "Name:\tgoogle.com\n", 17Name: google.com

[#5]

The DNS servers are virtual IP addresses - you cannot be sure of what any individual session might connect to. Do you have a static IP address?

[#6]

Moderators Note

This topic has been moved from ADSL Broadband to Everything Else

[#7]

I do indeed have a static IP.

(This , probably,  existed for several months before the 1st post, so if you have logs it may be possible to work out what real IP is was being directed at)

[FYI: Currently both are working]

[#8]

IIRC a static IP has a markedly different routing to the DNS servers, thus you reporting a fault and someone else testing and seeing no fault might not be a similar test.

As I noted, given that there is an array of servers delivering the DNS service behind the published IP addresses, there can be no assurance that one test to another test is actually executing on the same equipment.