Re: [gentoo-user] Browsers cannot access WWW while ping and host utilities work as expected.

[gevisz]

I somehow missed this post, so excuse me for the late reply.

2013/8/5 Mick <michaelkintzios@×××××.com>:
> On Monday 05 Aug 2013 07:06:08 gevisz wrote:
>> My thanks to all who replied to my question.
>>
>> The problem was with my local router, which I also used as DNS.
>> After excluding it from /etc/resolv.config and /etc/init.d/net files,
>> Firefox started to work as expected.
>
> Hmm ... I wonder if this is related to my earlier comment about malformed
> packets.

Somewhere, you hinted that the problem may be with the routers and
suggested to experiment with it.

Before that, I strongly believed that, if I listed 3 different routers in my
resolv.conf, the system should proceed with the next router if something
is wrong with the previous one, but unfortunately it did not.

The response of the first router contained an error that prevented all the
other applications to use it, the system knew about it (for example from
the output of the host utility) but, nevertheless did not proceeded with
the next router listed in resolv.conf.

I do undersand that this may be because of the layered structure of the
networked software. But, nevertheless, I think that something is fundamentally
wrong with this.

Once more, thank you for your help.

A few following remarks are minor and so, you can stop your reading here.

> May be worth trying a different firmware for this router.

I have already changed the firmware after purchasing it but now I cannot afford
it as I need its uninterupted functioning.

>> Suggestions of  Michael Kintzios
>
>> > This is the new kernel naming scheme of NICs.  Which-ever nomenclature
>> > you decide to use, check that that's the only one having a symlink in
>> > /etc/init.d to net.lo
>>
>> Yes, there is only enp2s15 links to lo in /etc/init.d
>
> The idea here is that you need consistent naming of your iface.  If you have
> settled on the kernel naming of enp2s15, then stick with this throughout your
> configuration.

Yes, I did.

>> After deleting all but my lan router DNS from /etc/conf.d/net and
>> /etc/resolv.conf files, I had the same problem as before but,
>> in addition, the host utility reports an additional error. Please,
>> see the full response below.
>
> You should not need to manually alter anything in your /etc/resolv.conf,
> which will be completed with the DNS server name(s) you have set up
> in your /etc/conf.d/net.

Actually, I changed it in both files simultaneously, but -- as I have already
explained it above, yes, I should not do it but had to. :^)

>> # host www.google.com
>> www.google.com has address 74.125.232.52
>> www.google.com has address 74.125.232.48
>> www.google.com has address 74.125.232.49
>> www.google.com has address 74.125.232.50
>> www.google.com has address 74.125.232.51
>> ;; Warning: query response not set
>> ;; Warning: query response not set
>
> I think this means that the DNS server response is incorrectly formed (or that
> the server respond code does not include a 4 bit RCODE as it should - more
> detail for DNS geeks can be found here:  http://www.ietf.org/rfc/rfc2136.txt)

Thank you, for the referrence. I will study it later.

>> Host www.google.com not found: 4(NOTIMP)
>
> The RFC says:  The name server does not support the specified Opcode.
> I would reflash the firmware, or try any OpenSource alternatives if available
> for your router.

It is a small router device. I have already changed its firmware after
purchasing it
to a newer one. I do not know if its open source alternative exists and, anyway,
I cannot change it now because I cannot afford any interruption of the
router functioning.

>> After leaving in /etc/conf.d/net and /etc/resolv.conf files only the
>> DNS of my service provider, Firefox started to work as predicted. Thank you!
>
> This may not be ideal (it will introduce some latency in your requests) but if
> you can't fix your router, it'll have to do for now.
>
>
>> > Can you please show us:
>> > ip route show
>> > ip addr show
>> > ip link show
>>
>> $ ip route show
>> default via 192.168.0.1 dev enp2s15  metric 2
>> 127.0.0.0/8 via 127.0.0.1 dev lo  scope link
>> 192.168.0.0/24 dev enp2s15  proto kernel  scope link  src 192.168.0.9
>
> This says that your IP address us 192.168.0.9, but see below.
>
>
>> $ ip addr show
> [snip ...]
>
>> 2: enp2s15: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc
>> pfifo_fast state UP qlen 1000
>>     link/ether <MAC_address_of_my_Ethernet_card> brd ff:ff:ff:ff:ff:ff
>>     inet 192.168.0.7/24 brd 192.168.0.255 scope global enp2s15
>
> This says that your ip address is 192.168.0.7 - did you get a different IP
> address between the two commands?  Your /etc/conf.d/net showed that you had
> set up a static address as config_enp2s15="192.168.0.9 ..."  so why is this
> here?

Sorry, it happened only because of my stupid attempt to eliminate all
the real IP addresses...

>> $ ip link show
> [snip ...]
>
>> 2: enp2s15: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc
>> pfifo_fast state UP mode DEFAULT qlen 1000
>>     link/ether <MAC_address_of_my_Ethernet_card> brd ff:ff:ff:ff:ff:ff
>
> OK, this looks good.
>
>
>> Suggestions of Kurian Thayil
>>
>> > Can you do a ping and see if the resolv.conf DNS ips are reachable?
>>
>> Yes, I can ping all my DNS. Moreover, I successfully use them from my
>> Ubuntu installation on the same computer.
>>
>> > do a
>> > dig @8.8.8.8 www.google.com ## which will do a name resolution with
>> > Google DNS servers.
>>
>> Here is the output:
>>
>> $ dig @8.8.8.8 www.google.co
>>
>> ; <<>> DiG 9.9.2 <<>> @8.8.8.8 www.google.co
>> ; (1 server found)
>> ;; global options: +cmd
>> ;; Got answer:
>> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4036
>> ;; flags: qr rd ra; QUERY: 1, ANSWER: 12, AUTHORITY: 4, ADDITIONAL: 5
>>
>> ;; OPT PSEUDOSECTION:
>> ; EDNS: version: 0, flags:; udp: 4096
>> ;; QUESTION SECTION:
>> ;www.google.co.                       IN      A
>>
>> ;; ANSWER SECTION:
>> www.google.co.                86400   IN      CNAME   www3.l.google.com.
>> www3.l.google.com.    13      IN      A       173.194.32.166
>> www3.l.google.com.    13      IN      A       173.194.32.167
>> www3.l.google.com.    13      IN      A       173.194.32.168
>> www3.l.google.com.    13      IN      A       173.194.32.169
>> www3.l.google.com.    13      IN      A       173.194.32.174
>> www3.l.google.com.    13      IN      A       173.194.32.160
>> www3.l.google.com.    13      IN      A       173.194.32.161
>> www3.l.google.com.    13      IN      A       173.194.32.162
>> www3.l.google.com.    13      IN      A       173.194.32.163
>> www3.l.google.com.    13      IN      A       173.194.32.164
>> www3.l.google.com.    13      IN      A       173.194.32.165
>>
>> ;; AUTHORITY SECTION:
>> google.com.           244594  IN      NS      ns3.google.com.
>> google.com.           244594  IN      NS      ns2.google.com.
>> google.com.           244594  IN      NS      ns4.google.com.
>> google.com.           244594  IN      NS      ns1.google.com.
>>
>> ;; ADDITIONAL SECTION:
>> ns1.google.com.               191550  IN      A       216.239.32.10
>> ns2.google.com.               191550  IN      A       216.239.34.10
>> ns3.google.com.               191550  IN      A       216.239.36.10
>> ns4.google.com.               191550  IN      A       216.239.38.10
>>
>> ;; Query time: 96 msec
>> ;; SERVER: 8.8.8.8#53(8.8.8.8)
>> ;; WHEN: Mon Aug  5 07:59:45 2013
>> ;; MSG SIZE  rcvd: 385
>
> OK, Google's public DNS 8.8.8.8 works fine, but your router's internal DNS
> repeater seems to be dodgy.

Yes, it is. Thank you once more (in case you happen to read until this point :).

> Regards,
> Mick