Re: Log errors of network

From: lnet@col7.metta.lk
Date: Wed Jan 12 2000 - 06:10:16 EST


On Tue, Jan 11, 2000 at 08:58:47AM +1100, Kendall Lister wrote:

> > I run qmail and that requres that I have a working DNS.
> > My DNS is sometimes not resolving when I try to log in via LAN.
> 'Sometimes' is a difficult problem to resolve; can you identify any
> particular times when it fails consistently? Also, when you say you 'log
> in via LAN', what exactly do you mean - are we talking telnet, Netatalk,
> Samba, or just plain DNS, which doesn't really have a sense of loggin in?

What I do is, get my mail to a Win98 machine via a lan connection from the
Redhat6.0 - I use Outlook express.

The same is for browsing my server with Netscape or Telnet the server by
name. I can telnet the port "172.16.1.2"

"named" normally checks which interfaces are available when it first
starts up and then every hour after that.

What is happening is that the interface for 172.16.1.1 is deleted after
some time and then my DNS will not answer the Lan query.

If I do a login via modem the ppp interface will again be up and the DNS
is listening on 172.16.1.1 and everything is OK again.

> > for my Dialup users I had the same problem To settle that I have put
> > "ndc reload" in /etc/ppp/ppp-on.local and that settled the problem.
> I'm afraid I don't know what ndc is or does.

ndc is a program that comes with the bind distribution
"ndc" will stop|start|restart|reload etc... "named"
 
> > I was looing for something like that in the LAN also, to make sure
> > that the DNS was working and up.
> DNS doesn't usually just stop working.
>Is your Internet link permanent?

I dial in to my ISP via a ppp link every now and then to get mail
(this is done by cron)

The DNS will clean up after 1 hour if there is no access
unless the interface-interval has been set to some different value.

/var/log/messages
Jan 11 22:49:00 narada named[6706]: deleting interface [172.16.1.1].53
(this is my ppp connection)

I have not seen the Lan connection being deleted. (172.16.1.2)

The strange thing is that the DNS will not answer my LAN query unless
it is also listening to the 172.16.1.1

ifconfig:
eth0 Link encap:Ethernet HWaddr 00:60:97:95:CA:C5
          inet addr:172.16.1.2 Bcast:172.16.255.255 Mask:255.255.0.0
          UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
          RX packets:6798 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4832 errors:0 dropped:0 overruns:0 carrier:0
          collisions:19 txqueuelen:100
          Interrupt:10 Base address:0x300
-------- route -n -------
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
172.16.1.2 0.0.0.0 255.255.255.255 UH 0 0 0 eth0
172.16.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
--------
there is no default gateway set as that comes up with my ppp connection
the below is when I dial out to my ISP.

Destination Gateway Genmask Flags Metric Ref Use Iface
203.115.29.130 0.0.0.0 255.255.255.255 UH 0 0 0 ppp0
172.16.1.2 0.0.0.0 255.255.255.255 UH 0 0 0 eth0
172.16.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
0.0.0.0 203.115.29.130 0.0.0.0 UG 0 0 0 ppp0

I do not see 172.16.1.1 If you see any errors in this please let me know.

This is the messages I get when restarting named after a ppp dialup.
/var/log/messages
Jan 12 08:58:00 narada named[11502]: starting. named 8.2.1 Thu Aug 12 21:00:37
LKT 1999 ^Iroot@narada.col7.metta.lk:/usr/local/src/dns/src/bin/named
Jan 12 08:58:00 narada named[11502]: hint zone "" (IN) loaded (serial 0)
Jan 12 08:58:00 narada named[11502]: master zone "col7.metta.lk" (IN) loaded (serial 2000011101)
Jan 12 08:58:00 narada named[11502]: master zone "0.0.127.in-addr.arpa" (IN) loaded (serial 1999083001)
Jan 12 08:58:00 narada named[11502]: master zone "1.16.172.in-addr.arpa" (IN) loaded (serial 2000011101)
Jan 12 08:58:00 narada named[11502]: listening on [127.0.0.1].53 (lo)
Jan 12 08:58:00 narada named[11502]: listening on [172.16.1.2].53 (eth0)
Jan 12 08:58:00 narada named[11502]: listening on [172.16.1.1].53 (ppp0)
Jan 12 08:58:00 narada named[11502]: Forwarding source address is
[0.0.0.0].1083Jan 12 08:58:00 narada named[11503]: Ready to answer queries.
Jan 12 08:58:00 narada named[11503]: sysquery: sendto([0.0.0.0].0): Invalid argument

If the interface 172.16.1.1 is up then the DNS on the lan will work.
The problem might be that my zone file is having 2 IP for the server "col7.metta.lk"

---------------------------
/var/named/pz/col7.metta.lk
---------------------------
$TTL 86400 ; default time-to-live - 24 hours
@ IN SOA narada.col7.metta.lk. metta.col7.metta.lk. (
                        2000011101 ; serial
                        86400 ; refresh
                        36000 ; retry
                        2592000 ; expire
                        86400 ; default_ttl
                        )
                IN NS narada.col7.metta.lk.
@ IN MX 10 narada.col7.metta.lk.
localhost IN A 127.0.0.1
narada IN A 172.16.1.1
narada IN MX 10 narada.col7.metta.lk.
narada IN A 172.16.1.2
dvf IN A 172.16.1.3
metta01 IN A 172.16.1.4
col7.metta.lk. IN A 172.16.1.1
col7.metta.lk. IN A 172.16.1.2
col7.metta.lk. IN MX 10 narada.col7.metta.lk.
---------------------------

Thanks for all your help
Jacob

-- 
 A saying of the Buddha from http://metta.lk/ 
 -------------------------------------------- 
Verily, from meditation arises wisdom. Without meditation wisdom wanes. Knowing this twofold path of gain and loss, let one so conduct oneself that wisdom may increase. 
Random Dhammapada Verse 282 
 
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