Sort DNS lookup

[normanzhang]

Hi,

I have VLAN1 (192.168.99.0/24) access DNS in VLAN2 (192.168.11.0/24). If a host in DNS is multihomed (e.g., 192.168.11.21, 192.168.22.21), VLAN1 does not know how to sort it. I can restrict the sorting in BIND using sortlist, but this has effect on 192.168.99.0/24. May I ask is there a IOS command that allows me to sort DNS lookup? I would like to receive 192.168.11.21 first.

Regards,

Norman Zhang

[normanzhang]

I think I found the problem. VLAN1 (192.168.99.0/24) is connected to VLAN2 (192.168.11.0/24). Hosts from VLAN1 is trying acccess 192.168.11.21 (multihomed mail server with default-gw = 192.168.22.21). Thus connection to 192.168.11.21 from VLAN1 fails then it fall-back to 192.168.22.21 which is in a different subnet.

What puzzles me, is that it worked for another multihomed host 192.168.11.2, 192.168.22.2. I had ip helper-address for 192.168.11.2 under VLAN1. Could someone please give me some pointers?

interface Vlan1

ip address 192.168.99.1 255.255.255.0

ip helper-address 192.168.11.2

ip helper-address 192.168.11.21

no ip mroute-cache

!

interface Vlan2

ip address 192.168.11.4 255.255.255.0

no ip mroute-cache

192.168.11.4 is the IP for my current switch.

[shajain · Accepted solution]

Add a route for 192.168.99.0 network in your DNS server.

[normanzhang]

Thanks. You are absolutely correct. I just recall that I added static route to the other multihomed server, and that's why it worked them.

What's the best way of adding static route to those multihomed servers?

[shajain]

If it is Windows machine use

route -p add mask

If it is Unix define it /etc/rc2.d/S69inet file