Re: IPv6 fail

[Alexander Malysh]

For MySql connection Kannel libs are not used. Kannel uses MySQL client library 
and therefore
there is something different wrong because MySQL client libs supports IPV6.

Alex

> Am 20.07.2020 um 10:28 schrieb Antony Stone 
> :
> 
> On Monday 20 July 2020 at 08:48:39, Alexander Malysh wrote:
> 
>> Hi,
>> 
>> Kannel always take the first IP from DNS response. Therefore you have to
>> make sure IPV4 address is the first address,
> 
> Er, you can't do that with DNS.  Records are returned from the resolver in a 
> random order on each request, in a deliberate effort to spread out the load 
> on 
> servers.
> 
> On Monday 20 July 2020 at 09:07:15, Alexander Malysh wrote:
> 
>> Hmm, looking into the code Kannel should connect just fine even DNS
>> resolves to IPV4 and IPV6.
>> 
>> Please check in your logs in debug mode for:
>> 
>> Connecting to <%s>
>> 
>> AND
>> 
>> connect to <%s> failed
> 
> I see no "Connecting to" messages for the hostname in question.
> 
> I do see:
> 
> 2020-07-20 09:18:19 [6053] [0] ERROR: MYSQL: Can't connect to MySQL server on 
> 'server.example.com' (111 "Connection refused")
> 
> 2020-07-20 09:18:19 [6053] [0] PANIC: SQLBOX: MySQL: database pool has no 
> connections!
> 
> 2020-07-20 09:18:19 [6143] [0] ERROR: MYSQL: can not connect to database!
> 
> Now, the "connection refused" part puzzled me - it looked like kannel was 
> connecting to MySQL but MySQL was saying "go away", so I set up tshark to 
> capture packets to/from port 3306, and what I see is that an *IPv6* 
> connection 
> *is being made* between the two servers, there's a login request, an 'OK' 
> response and then the connection gets closed.
> 
> I'm going to investigate this a bit more to see exactly what query and 
> response are being exchanged, once I can spend a bt of time with a broken 
> system again.
> 
> 
> Thanks for the assistance,
> 
> 
> Antony.
> 
> -- 
> A few words to be cautious of between American and English:
> - momentarily
> - suspenders
> - chips
> - pants
> - jelly
> - pavement
> - vest
> - pint (and gallon)
> - pissed
> 
> 
>   Please reply to the list;
> please *don't* CC me.
> 

Re: IPv6 fail

[Antony Stone]

On Monday 20 July 2020 at 08:48:39, Alexander Malysh wrote:

> Hi,
> 
> Kannel always take the first IP from DNS response. Therefore you have to
> make sure IPV4 address is the first address,

Er, you can't do that with DNS.  Records are returned from the resolver in a 
random order on each request, in a deliberate effort to spread out the load on 
servers.

On Monday 20 July 2020 at 09:07:15, Alexander Malysh wrote:

> Hmm, looking into the code Kannel should connect just fine even DNS
> resolves to IPV4 and IPV6.
> 
> Please check in your logs in debug mode for:
> 
> Connecting to <%s>
> 
> AND
> 
> connect to <%s> failed

I see no "Connecting to" messages for the hostname in question.

I do see:

2020-07-20 09:18:19 [6053] [0] ERROR: MYSQL: Can't connect to MySQL server on 
'server.example.com' (111 "Connection refused")

2020-07-20 09:18:19 [6053] [0] PANIC: SQLBOX: MySQL: database pool has no 
connections!

2020-07-20 09:18:19 [6143] [0] ERROR: MYSQL: can not connect to database!

Now, the "connection refused" part puzzled me - it looked like kannel was 
connecting to MySQL but MySQL was saying "go away", so I set up tshark to 
capture packets to/from port 3306, and what I see is that an *IPv6* connection 
*is being made* between the two servers, there's a login request, an 'OK' 
response and then the connection gets closed.

I'm going to investigate this a bit more to see exactly what query and 
response are being exchanged, once I can spend a bt of time with a broken 
system again.


Thanks for the assistance,


Antony.

-- 
A few words to be cautious of between American and English:
 - momentarily
 - suspenders
 - chips
 - pants
 - jelly
 - pavement
 - vest
 - pint (and gallon)
 - pissed


   Please reply to the list;
 please *don't* CC me.

Re: IPv6 fail

[Alexander Malysh]

Hmm, looking into the code Kannel should connect just fine even DNS resolves to 
IPV4 and IPV6.

Please check in your logs in debug mode for:

Connecting to <%s>

AND

connect to <%s> failed

Thanks,
Alex

> Am 20.07.2020 um 08:48 schrieb Alexander Malysh :
> 
> Hi,
> 
> Kannel always take the first IP from DNS response. Therefore you have to make 
> sure IPV4
> address is the first address,
> 
> Alex
> 
> 
>> Am 19.07.2020 um 15:43 schrieb Antony Stone 
>> > >:
>> 
>> On Sunday 19 July 2020 at 15:04:45, Alexander Malysh wrote:
>> 
>>> Hi,
>>> 
>>> kannel doesn’t support IPV6 yet.
>> 
>> Hm, it appears to be even worse than I thought...
>> 
>> I was switching from a config file which contained the hostname of a server 
>> which only had an IPv4 address, to a hostname which only resolves to an IPv6 
>> address.
>> 
>> Since kannel doesn't do IPv6 yet, that didn't work.
>> 
>> However today I seem to have found that if you give kannel a hostname which 
>> resolves to both IPv4 and IPv6 addresses, it still can't connect to the IPv4 
>> address!
>> 
>> Just the existence of an IPv6 address in the hostname lookup is enough to 
>> prevent kannel from being able to connect to the IPv4 address alongside it.
>> 
>> 
>> Can anyone else confirm this finding, or is it just me and my networking 
>> setup 
>> (which works fine for other services connecting to both IPv4 and IPv6 
>> addresses 
>> for the same hostname)?
>> 
>> 
>> Thanks,
>> 
>> 
>> Antony.
>> 
>> -- 
>> "When you talk about Linux versus Windows, you're talking about which 
>> operating system is the best value for money and fit for purpose. That's a 
>> very 
>> basic decision customers can make if they have the information available to 
>> them. Quite frankly if we lose to Linux because our customers say it's 
>> better 
>> value for money, tough luck for us."
>> 
>> - Steve Vamos, MD of Microsoft Australia
>> 
>>   Please reply to the list;
>> please *don't* CC me.
>> 
>> 
> 

Re: IPv6 fail

[Alexander Malysh]

Hi,

Kannel always take the first IP from DNS response. Therefore you have to make 
sure IPV4
address is the first address,

Alex


> Am 19.07.2020 um 15:43 schrieb Antony Stone 
> :
> 
> On Sunday 19 July 2020 at 15:04:45, Alexander Malysh wrote:
> 
>> Hi,
>> 
>> kannel doesn’t support IPV6 yet.
> 
> Hm, it appears to be even worse than I thought...
> 
> I was switching from a config file which contained the hostname of a server 
> which only had an IPv4 address, to a hostname which only resolves to an IPv6 
> address.
> 
> Since kannel doesn't do IPv6 yet, that didn't work.
> 
> However today I seem to have found that if you give kannel a hostname which 
> resolves to both IPv4 and IPv6 addresses, it still can't connect to the IPv4 
> address!
> 
> Just the existence of an IPv6 address in the hostname lookup is enough to 
> prevent kannel from being able to connect to the IPv4 address alongside it.
> 
> 
> Can anyone else confirm this finding, or is it just me and my networking 
> setup 
> (which works fine for other services connecting to both IPv4 and IPv6 
> addresses 
> for the same hostname)?
> 
> 
> Thanks,
> 
> 
> Antony.
> 
> -- 
> "When you talk about Linux versus Windows, you're talking about which 
> operating system is the best value for money and fit for purpose. That's a 
> very 
> basic decision customers can make if they have the information available to 
> them. Quite frankly if we lose to Linux because our customers say it's better 
> value for money, tough luck for us."
> 
> - Steve Vamos, MD of Microsoft Australia
> 
>   Please reply to the list;
> please *don't* CC me.
>