RE: multiple network cards and dns

2006-12-31 Thread Andrew Critchlow 
That's brilliant thanks for that!
I am going to be setting up a proxy server using Squid with 2 network cards. I 
am right in saying the routing table should have a default out the external 
interface.
Also the reason i was asking about dns is that as im using this box as a proxy 
what dns servers should i specify? Ones on the inside network, the isp's 
(external network), or both of them?
 
 
 
 
many thanks


Date: Sun, 31 Dec 2006 12:30:50 -0700From: [EMAIL PROTECTED]: [EMAIL 
PROTECTED]: Re: multiple network cards and dns
Andrew Critchlow wrote: 


When you have 2 network cards in use with debian with DNS server configured on 
each which one does it choose to query for an address?  Is configuring 2 
network cards on debian as simple as configuring one card?  thanks everyone.DNS 
is a map of names to numbers and numbers to names. You can basically assign any 
name to each IP for each NIC. If you assign the same name to two IP address, 
BIND DNS will rotate the responses in a round robin fashion. So:foo.bar.   IN   
A   192.168.1.1foo.bar.   IN   A   192.168.1.2Will first respond to 
queries:192.168.1.1 192.168.1.2Then will respond:192.168.1.2 192.168.1.1This is 
a load balancing feature of BIND 4.9 and later versions, if this is what you 
are trying to accomplish. Otherwise if it's a firewall, assign a different name 
to the internal and external IPs.Configuring two NICs is as simple as adding 
another entry in /etc/network/interfaces for the new NIC. Be careful as 
sometimes after adding a second NIC the original NIC may become eth1 rather 
than eth0 (this has been PCI slot placement dependent for me).Here's the 
/etc/network/interfaces file from my firewall:# This file describes the network 
interfaces available on your system# and how to activate them. For more 
information, see interfaces(5).auto lo eth0 eth1# The loopback network 
interfaceiface lo inet loopback# The internal (onboard) network interfaceiface 
eth1 inet staticaddress 192.168.1.254netmask 255.255.255.0  
  network 192.168.1.0broadcast 192.168.1.255#gateway 
192.168.1.254# The external (pci) network interfaceiface eth0 inet static   
 address 55.55.55.105netmask 255.255.255.0network 55.55.55.0
broadcast 55.55.55.255gateway 55.55.55.254Note the commented out 
gateway for eth1. Since this is a firewall the appropriate gateway is the 
external one and if both gateways are enabled routes get screwed up. I know as 
I've had this hang me up before...-Ryan

Re: multiple network cards and dns

2006-12-31 Thread Ryan Castleberry 

Andrew Critchlow wrote:
When you have 2 network cards in use with debian with DNS server 
configured on each which one does it choose to query for an address?
 
 
Is configuring 2 network cards on debian as simple as configuring one 
card?
 
 
thanks everyone.
DNS is a map of names to numbers and numbers to names. You can basically 
assign any name to each IP for each NIC. If you assign the same name to 
two IP address, BIND DNS will rotate the responses in a round robin 
fashion.


So:
foo.bar.   IN   A   192.168.1.1
foo.bar.   IN   A   192.168.1.2

Will first respond to queries:
192.168.1.1 192.168.1.2
Then will respond:
192.168.1.2 192.168.1.1

This is a load balancing feature of BIND 4.9 and later versions, if this 
is what you are trying to accomplish. Otherwise if it's a firewall, 
assign a different name to the internal and external IPs.


Configuring two NICs is as simple as adding another entry in 
/etc/network/interfaces for the new NIC. Be careful as sometimes after 
adding a second NIC the original NIC may become eth1 rather than eth0 
(this has been PCI slot placement dependent for me).


Here's the /etc/network/interfaces file from my firewall:

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

auto lo eth0 eth1

# The loopback network interface
iface lo inet loopback

# The internal (onboard) network interface
iface eth1 inet static
   address 192.168.1.254
   netmask 255.255.255.0
   network 192.168.1.0
   broadcast 192.168.1.255
   #gateway 192.168.1.254

# The external (pci) network interface
iface eth0 inet static
   address 55.55.55.105
   netmask 255.255.255.0
   network 55.55.55.0
   broadcast 55.55.55.255
   gateway 55.55.55.254


Note the commented out gateway for eth1. Since this is a firewall the 
appropriate gateway is the external one and if both gateways are enabled 
routes get screwed up. I know as I've had this hang me up before...


-Ryan

multiple network cards and dns

2006-12-31 Thread Andrew Critchlow 
When you have 2 network cards in use with debian with DNS server configured on 
each which one does it choose to query for an address?
 
 
Is configuring 2 network cards on debian as simple as configuring one card?
 
 
thanks everyone.