About /etc/resolv.conf

satimis · 02-15-2006, 09:41 PM

Hi folks,

I need to set following nameservers permanent on /etc/resolv.conf e.g.

Code:

nameserver 222.222.222.222
nameserver 111.111.111.111

Because my ISP always assign;
nameserver 111.111.111.111 (primary)
nameserver 222.222.222.222 (secondary)

the primary having problem. I need to revert their order.

On /etc/sysconfig/network-scripts/ifcfg-xxx

Code:

# Please read /usr/share/doc/initscripts-*/sysconfig.txt
# for the documentation of these parameters.
IPV6INIT=no
USERCTL=no
PEERDNS=yes
TYPE=xDSL
DEVICE=ppp0
BOOTPROTO=dialup
PIDFILE=/var/run/pppoe-adsl.pid
FIREWALL=NONE
PING=.
PPPOE_TIMEOUT=80
LCP_FAILURE=3
LCP_INTERVAL=20
CLAMPMSS=1412
CONNECT_POLL=6
CONNECT_TIMEOUT=60
PERSIST=no
SYNCHRONOUS=no
DEFROUTE=yes
USER='satimis_lms@icare.com.hk'
ETH=eth0
PROVIDER=Icare_BB
DEMAND=no
ONBOOT=yes

Whether change both;

Code:

USERCTL=no
PEERDNS=yes

to

Code:

USERCTL=yes
PEERDNS=no

or only changing "PEERDNS=no"

I read "/usr/share/doc/initscripts-*/sysconfig.txt" but I am not very clear.

Please advise. TIA

B.R.
satimis

cdjc · 02-16-2006, 12:32 AM

Set PEERDNS to "no"

Code:

PEERDNS=no

Then, restart your network and edit resolv.conf to match what you want.

satimis · 02-16-2006, 01:42 AM

Hi cdjc,

Tks for your advice. It works.

Steps performed as follows;

1) edited /etc/sysconfig/network-scripts/ifcfg-xxx
2) Set PEERDNS=no
3) ran
# /etc/rc.d/init.d/network restart
4) edited /etc/resolv.conf
typing nameservers as needed there

That is all.

Tested with;
# /etc/rc.d/init.d/network restart
twice to confirm /etc/resolv.conf not overwritten.

Tks.

What are following nameservers;

Code:

nameserver 218.102.32.208
nameserver 203.198.23.208

After editing /etc/sysconfig/network-scripts/ifcfg-xxx I found
them on; /etc/resolv.conf on fisrt restarting;
/etc/rc.d/init.d/network

But the broadband connected. Ping them found they were working without packet loss

B.R.
satimis

thew00t · 02-16-2006, 10:32 AM

Quote:

Originally Posted by satimis

What are following nameservers;

Code:

nameserver 218.102.32.208
nameserver 203.198.23.208

After editing /etc/sysconfig/network-scripts/ifcfg-xxx I found
them on; /etc/resolv.conf on fisrt restarting;
/etc/rc.d/init.d/network

Hi Satimis, looks like your name servers given there point to http://www.netvigator.com/ Seems to be a broadband supplier/web portal...the site's default language is Chinese.

w00t

Jaxån · 02-16-2006, 06:25 PM

I don't think it realy matter which order you put name servers in /etc/resolv.conf

The propper way to use one or more servers is to load balance between them. That is, with two servers, the questions should be divided between them, even if one is down or has other problems.

So your solution would be to dropp 111.111.111.111 all together and only use 222.222.222.222

satimis · 02-16-2006, 07:36 PM

Hi Jaxån,

Tks for your advice.

Quote:

The propper way to use one or more servers is to load balance between them.

I'm running a workstation only.

I put them on /etc/resolv.conf just reverting their order. In case my ISP fixes the problem I have 2 nameservers there switching between them.

B.R.
satimis

Jaxån · 02-16-2006, 08:03 PM

You might have missunderstod me. I wasn't that clear in my answer to you.

The servers I mean in my answer is the dns servers your ISP gives you.

If you have two DNS servers in your /etc/resolv.conf, your machine should ask each one every second time. That is, first DNS question should go to 111.111.111.111, next DNS question to 222.222.222.222, third to 111.111.111.111 and so on.

So you can't tell your machine (without a hack any way) to ask only 111.111.111.111 and only 222.222.222.222 when 111.111.111.111 has problems (which ever that could be).

So it doesn't matter which order you specify your DNS-servers in /etc/resolv.conf You will hit the bad server with problems each second time you do a DNS-question whichever order you use.

satimis · 02-16-2006, 08:58 PM

Hi thew00t,

Quote:

Seems to be a broadband supplier/web portal...

Noted with tks.

satimis

satimis · 02-16-2006, 09:06 PM

Hi Jaxån,

Quote:

So you can't tell your machine (without a hack any way) to ask only 111.111.111.111 and only 222.222.222.222 when 111.111.111.111 has problems (which ever that could be)

I expect it hits the 2nd nameserver assigned first.

Which option shall I set on /etc/sysconfig/network-scripts/ifcfg-xxx

Code:

# Please read /usr/share/doc/initscripts-*/sysconfig.txt
# for the documentation of these parameters.
IPV6INIT=no
USERCTL=no
PEERDNS=yes
TYPE=xDSL
DEVICE=ppp0
BOOTPROTO=dialup
PIDFILE=/var/run/pppoe-adsl.pid
FIREWALL=NONE
PING=.
PPPOE_TIMEOUT=80
LCP_FAILURE=3
LCP_INTERVAL=20
CLAMPMSS=1412
CONNECT_POLL=6
CONNECT_TIMEOUT=60
PERSIST=no
SYNCHRONOUS=no
DEFROUTE=yes
USER='satimis'
ETH=eth0
PROVIDER=xxx
DEMAND=no
ONBOOT=yes

TIA

B.R.
satimis

Jaxån · 02-17-2006, 11:14 AM

You can't select order to ask or which name server to ask first hand.
Your system will ask each name server in turn. One after the other in a round robin way. No option (that I know of any way).

If you don't want to use a name server, don't put it in /etc/resolv.conf

Oh yes, you need to tell pppd to not set dns server in /etc/resolv.conf by seting PEERDNS to no, as you have been told earlier. If you have PEERDNS=yes, pppd will ask for a list of DNS servers when you connect and use them.
That is if you use pppd or dhcp to get internet connection. Isn't it documented in /usr/share/doc/initscripts-*/sysconfig.txt ?

But this look like a Red Hat type of configuration. And I only uses Debian. But the way name reolution behaves is the same between RH and Debian. It's only the way system configuration is set up that is different.

satimis · 02-24-2006, 09:30 PM

Hi Jaxån,

Quote:

And I only uses Debian. But the way name reolution behaves is the same between RH and Debian. It's only the way system configuration is set up that is different.

Yes, it is the same. I got it. Tks

B.R.
satimis