My dear friend,
TCP/IP is a protocol with KNOWLEDGE at ICMP level(see RFC792 ).
The DNS server have a different purpose(see RFC 1034 or RFC 952 "HostNames
table").
Ping work at ICMP level.
The KERNEL is responsible about what is happened in the OS including the
TCP/IP protocol.
The TCP/IP IPV4/IPV6 and functions like
socket(),accept(),listen(),bind()...etc are implemented on the KERNEL
level...also the sockaddr structure type and many others.
Functions like gethostbyname(),gethostbyaddr(),res_init,res_query()...etc
and hostent structure type are implemented in glibc.
Without all this, the TCP/IP communication CAN NOT EXIST.
MySQL have the own way/functions for resolving hostnames but which is based
on the glibc functions.
The glibc defines the SYSTEM CALLS and others functions and it used by the
C/C++ compiler.
In fact by adding IP address in /etc/hosts, the glibc function
gethostbyaddr() reserve the RIGHT MEMORY SIZE FOR IT(seems to be a recast to
int type).
If the IP address/Alias is not present in "hosts", this function make an
wrong allocation memory and for this MySQL daemon is crashed.
That's it.
In my previous e-mail i don't say nothing about Domain Class(A,B,C) or
canonical name or reverse lookup or other things which is on DNS
responsibility.I try to say about how it work and was my wish to not to be
too technical.
Regards,
Gelu
_____________________________________________________
G.NET SOFTWARE COMPANY
Permanent e-mail address : [EMAIL PROTECTED]
[EMAIL PROTECTED]
----- Original Message -----
From: "Iikka Meriläinen" <[EMAIL PROTECTED]>
To: "Gelu Gogancea" <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Wednesday, October 23, 2002 2:11 PM
Subject: Re: RedHat 8 and mysql-server-3.23.52-3
Hi!
On Wed, 23 Oct 2002, Gelu Gogancea wrote:
> Hi Iikka,
>
> My opinion:
> Doesn't matter what type of client it is(whatever OS).TCP/IP it's the same
> for all.One property of the SERVER it to resolving hosts.And this is done
by
IP-hostname mapping/resolving is usually done by DNS servers, not the MySQL
server, assuming that they're not running on the same box. :-) There are
several ways for resolving addresses.
> using
> KERNEL functions.By adding in "hosts" file(in the SERVER MACHINE) the IP
> address of the client machine which want to connect to the SERVER, help
> SERVER for resolving the hostname.KERNEL make a lookup to the hostnames
> which is associate with the IP address.
AFAIK, IP-to-hostname mapping isn't done by _kernel_ functions. At least
the Linux kernel knows very little about hostnames. Some exotic Unixes may
implement this differently, but no operating system I'm aware of has kernel
interfaces for name resolution.
Making the server recognize the client correctly with an updated /etc/hosts
seems logical enough. It's strange, though, to have to make changes on the
server for clients to be able to connect.
> For using this functions IS NEED TO HAVE the properly "system call"
library
> which is(in this case) GLIBC.2.2.40.If some incompatibilities(BUGS) exists
> between this, a lot of problems can be raised after compilation.For this
> reason EGOR send a strongly message to all to make a downgrade to a
version
> of glibc which is stable.
Here you get it right. glibc is much more responsible for
ip-hostname-mapping than the operating system kernel itself. Kernel
implements the IP protocol with dotted-format addresses, and it expects
user-mode libraries to do any necessary conversions. That is, when you do
this: ping www.google.com the ping binary calls a couple of conversion
functions in user-mode libraries so that it can pass a real IP address to
the kernel/protocol interface.
> Personally, i can't do that because i have installed and others
applications
> which require this version(2.2.40) of glibc.For me was a compromised
> solution because i use Red Hat 8.0 and MySQL 4.0.4 for testing purpose.My
> applications run under Suse 7.x with MySQL 3.x (MyISAM).
> The problem was for who which make have installed MySQL from Source
> Distribution or Red Hat distribution.
> I hope you understand exactly what i try to say.Unfortunately (for me),my
> english is not so good .
Yep, I saw it. :-) But got your point anyway though.
Best regards,
Iikka
> ----- Original Message -----
> From: "Iikka Meriläinen" <[EMAIL PROTECTED]>
> To: "Gelu Gogancea" <[EMAIL PROTECTED]>
> Cc: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
> Sent: Wednesday, October 23, 2002 9:25 AM
> Subject: Re: RedHat 8 and mysql-server-3.23.52-3
>
>
> On Tue, 22 Oct 2002, Gelu Gogancea wrote:
>
> > Hi,
> > No.On the server machine.The "hosts" is the way for resolving
hostnames.In
> > other Unix system, like SCO, to put the IP address and the alias in
hosts
> is
> > indispensable.
>
> Well, I meant that the client machine in this case seems to be a *NIX, so
> the /etc/hosts of _that_ machine should be updated. Of course, depending
on
> where the error comes from. In this case it seems to be on the client
side -
> although the client computer seems to be running Unix.
>
> Iikka
>
> > ----- Original Message -----
> > From: "Iikka Meriläinen" <[EMAIL PROTECTED]>
> > To: "Gelu Gogancea" <[EMAIL PROTECTED]>
> > Cc: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
> > Sent: Tuesday, October 22, 2002 3:01 PM
> > Subject: Re: RedHat 8 and mysql-server-3.23.52-3
> >
> >
> > On Tue, 22 Oct 2002, Gelu Gogancea wrote:
> >
> > > Hi,
> > >
> > > Try to put in the /etc/hosts the IP address of the machine which must
> > > connect to the server.
> > >
> > Hi!
> >
> > I guess you mean the /etc/hosts on the client machine? Right?
> >
> > Also, updating your real DNS records might prove useful in the long run.
> >
> > Best regards,
> > Iikka
> >
> > > > I have recently installed RedHat 8 and the following RPMs:
> > > >
> > > > [root@chimp etc]# rpm -q mysql
> > > > mysql-3.23.52-3
> > > >
> > > > [root@chimp etc]# rpm -q mysql-server
> > > > mysql-server-3.23.52-3
> > > >
> > > > I am having problems connecting to the server remotely through the
TCP
> > > > connection, the firewall is completely disabled:
> > > >
> > > > njc2@hilton njc2/mysql/bin> mysqladmin -h chimp.battlemonkey.net -p
> > > > version
> > > > Enter password:
> > > > mysqladmin: connect to server at 'chimp.battlemonkey.net' failed
> > > > error: 'Lost connection to MySQL server during query'
> > > >
> > > > I can connect fine from the localhost to the socket:
> > > >
> > > > [root@chimp etc]# mysqladmin version -p
> > > > Enter password:
> > > > mysqladmin Ver 8.23 Distrib 3.23.52, for pc-linux-gnu on i686
> > > > Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
> > > > This software comes with ABSOLUTELY NO WARRANTY. This is free
> software,
> > > > and you are welcome to modify and redistribute it under the GPL
> license
> > > >
> > > > Server version 3.23.52-log
> > > > Protocol version 10
> > > > Connection Localhost via UNIX socket
> > > > UNIX socket /var/lib/mysql/mysql.sock
> > > > Uptime: 2 min 21 sec
> > > >
> > > > Threads: 1 Questions: 1 Slow queries: 0 Opens: 6 Flush tables: 1
> > > > Open tables: 0 Queries per second avg: 0.007
> > > >
> > > > This is the first part of /etc/my.cnf.
> > > >
> > > > [client]
> > > > #password = your_password
> > > > port = 3306
> > > > socket = /var/lib/mysql/mysql.sock
> > > >
> > > > # Here follows entries for some specific programs
> > > >
> > > > # The MySQL server
> > > > [mysqld]
> > > > port = 3306
> > > > socket = /var/lib/mysql/mysql.sock
> > > > skip-locking
> > > > set-variable = key_buffer=16M
> > > > set-variable = max_allowed_packet=1M
> > > > set-variable = table_cache=64
> > > > set-variable = sort_buffer=512K
> > > > set-variable = net_buffer_length=8K
> > > > set-variable = myisam_sort_buffer_size=8M
> > > > log-bin
> > > > server-id = 1
> > > >
> > > > Could it be something to do with the startup/stop script because I
> > > > noticed something else odd. The script works for starting the
daemon:
> > > >
> > > > [root@chimp etc]# /sbin/service mysqld start
> > > > Starting MySQL: [ OK ]
> > > >
> > > > But not for stopping it:
> > > >
> > > > [root@chimp etc]# /sbin/service mysqld stop
> > > > Stopping MySQL: [FAILED]
> > > >
> > > > I can only stop the daemon with:
> > > >
> > > > [root@chimp etc]# mysqladmin -p shutdown
> > > >
> > > > Thanks in advance,
> > > >
> > > > nicholas calugar
> > > >
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