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Author Network changed / System DNS broken / Help Please
whansen_at_corporate-image_dot_com@us.com

2004-04-28, 5:34 pm

my address ( whansen at corporate-image dot com )

<Problem>
After changing the network over from 192.168.0 to 192.168.33 I noticed
that one of my PERL apps was not sending mail out. Upon investigation
it was not able to resolve outgoing names properly. I discovered that
nubers would work fine for everything but that DNS worked correctly
some times and not correctly others.

The new load ballancing router seems to choose randomly between the
two WAN connections for each session. As the symptoms are consistant
and not random I do not beleive this to be a source of trouble. Also
both connections go to the same ISP so the two DNS servers are the
same for both connections.

I keep thinking I have missed something in re-configuring for the
192.168.33 network. I have included notes on the network and all the
important files/information I could think of below:

<Network>
1 Load ballancing router 192.168.100.100 acting as gateway and
providing nat. connected to two internet connections. Routing http/etc
to second router

1 Secondary router 192.168.33.100 acting as gateway and providing nat.
connected to lan. routing http/etc to server

Ports are unhindered for outgoing connections. A half dozen win
machines are experiencing no problems on the 192.168.33 network.

<Symptoms>

[root@amanda root]# host www.sonic.net
www.sonic.net has address 209.204.190.64
[root@amanda root]# ping www.sonic.net
ping: unknown host www.sonic.net
[root@amanda root]# ping 209.204.190.64
PING 209.204.190.64 (209.204.190.64) from 192.168.33.211 : 56(84)
bytes of data.
64 bytes from 209.204.190.64: icmp_seq=1 ttl=249 time=23.8 ms
64 bytes from 209.204.190.64: icmp_seq=2 ttl=251 time=36.6 ms
64 bytes from 209.204.190.64: icmp_seq=3 ttl=251 time=57.1 ms

--- 209.204.190.64 ping statistics ---
3 packets transmitted, 3 received, 0% loss, time 2021ms
rtt min/avg/max/mdev = 23.802/39.199/57.193/13.754 ms
[root@amanda root]# traceroute www.sonic.net
traceroute: unknown host www.sonic.net
[root@amanda root]# traceroute 209.204.190.64
traceroute to 209.204.190.64 (209.204.190.64), 30 hops max, 38 byte
packets
1 router (192.168.33.100) 2.119 ms 1.294 ms 1.263 ms
2 192.168.100.100 (192.168.100.100) 3.150 ms 3.225 ms 3.200 ms
3 64.142.68.1 (64.142.68.1) 15.960 ms 16.091 ms 16.008 ms
4 64.142.32.1 (64.142.32.1) 171.970 ms 17.529 ms 17.946 ms
5 64.142.0.85 (64.142.0.85) 19.669 ms 20.885 ms 20.911 ms
6 208.201.224.120 (208.201.224.120) 23.108 ms 21.119 ms 21.271 ms
[root@amanda root]#



<System>

Red Hat Linux release 8.0 (Psyche)

[root@amanda etc]# cat hosts
# Do not remove the following line, or various programs
# that require network functionality will fail.
#servers

#ivr boxes

127.0.0.1 localhost
192.168.33.211 amanda amanda.corporate-image.com
192.168.33.210 clara
192.168.33.220 mabel
192.168.33.100 router

[root@amanda etc]# cat /etc/resolv.conf
domain corporate-image.com
search corporate-image.com
nameserver 208.201.224.11
nameserver 208.201.224.33

[root@amanda sysconfig]# cat network
NETWORKING=yes
HOSTNAME=amanda

[root@amanda network-scripts]# cat ifcfg-eth0
DEVICE=eth0
BOOTPROTO=none
BROADCAST=192.168.33.255
IPADDR=192.168.33.211
NETMASK=255.255.255.0
NETWORK=192.168.33.0
ONBOOT=yes
USERCTL=no
PEERDNS=no
TYPE=Ethernet
GATEWAY=192.168.33.100

[root@amanda root]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:D0:B7:88:53:66
inet addr:192.168.33.211 Bcast:192.168.33.255
Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:13943 errors:0 dropped:0 overruns:0 frame:6
TX packets:19084 errors:0 dropped:0 overruns:0 carrier:2
collisions:388 txqueuelen:100
RX bytes:2534201 (2.4 Mb) TX bytes:2652123 (2.5 Mb)
Interrupt:21

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:27 errors:0 dropped:0 overruns:0 frame:0
TX packets:27 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:3032 (2.9 Kb) TX bytes:3032 (2.9 Kb)

[root@amanda etc]# cat host.conf
order hosts,bind
[root@amanda etc]#


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