Sorry for the late reply, I was on holiday last week:

The servers behind our css are using the internet dns, and they don't seem to have any problem with that.
But our firewall and ids's aren't happy with this behaviour, and their logs are running full at immense speed.

The reduced configuration below:

HVD.

!Generated on 03/13/2006 11:45:11 
!Active version: sg0740104s 

configure 


!*************************** GLOBAL *************************** 
  no restrict web-mgmt  
  ip no-implicit-service  
  virtual authentication primary tacacs  
  virtual authentication secondary local  
  acl enable  
  global-portmap base-port 3000 range 30000  
  sntp server x.x.x.200 version 1  

  snmp trap-type enterprise  

  snmp community xxxx read-only  
  snmp community xxxx read-write  
  snmp trap-host x.x.x.200 xxxxxxx  
  snmp trap-host x.x.x.201 xxxxxxx  
  snmp trap-type enterprise service-transition  
  snmp trap-type enterprise redundancy-transition  
  snmp trap-type enterprise reload  
  snmp trap-type enterprise isc-lifetick-failure  
  snmp name "csbrumz3"  

  logging host x.x.x.200 facility 3 log-level debug-7  
  logging disk system.log  
  logging subsystem netman level info-6  
  logging subsystem circuit level info-6  
  logging subsystem redundancy level info-6  
  logging subsystem keepalive level info-6  
  logging subsystem vrrp level info-6  

  dns suffix xxxxxxx
  dns primary y.y.y.210  
  dns secondary y.y.y.211  

  tacacs-server key xxxxxxxx
  tacacs-server x.x.19.200 49 primary  
  tacacs-server x.x.17.200 49  
  tacacs-server timeout 60  

  ip route 0.0.0.0 0.0.0.0 y.y.y.126 1  

!************************* INTERFACE ************************* 
interface  2/1 
  bridge vlan 19  

interface  2/3 
  bridge vlan 18  

interface  2/8 
  isc-port-one  

!************************** CIRCUIT ************************** 
circuit VLAN1 

  ip address 169.254.1.3 255.255.255.0  

circuit VLAN19 

  ip address y.y.y.115 255.255.255.128  
    ip virtual-router 1 priority 210 preempt  
    ip redundant-vip 1 y.y.y.66  
circuit VLAN18 

  ip address x.x.18.248 255.255.255.0  
    ip virtual-router 2 priority 210 preempt  
    ip redundant-interface 2 x.x.18.254  


!************************** SERVICE ************************** 
service our_system1  
  keepalive retryperiod 60  
  keepalive frequency 20  
  keepalive maxfailure 2  
  keepalive port 80  
  ip address x.x.18.129  
  redundant-index 101  
  keepalive uri "/poll/poll.htm"  
  keepalive type http non-persistent  
  active  

service our_system2
  keepalive retryperiod 120  
  keepalive frequency 60  
  keepalive maxfailure 2  
  keepalive port 80  
  ip address x.x.18.130 
  keepalive type http  
  keepalive uri "/poll/poll.htm"  
  redundant-index 107  
  active 

service server5  
  redundant-index 160  
  ip address x.x.18.67  
  active  

service server6  
  ip address x.x.18.68  
  redundant-index 161  
  active  


!*************************** OWNER *************************** 
owner WEARE 

content our_system  
    advanced-balance sticky-srcip  
    add service our_system1  
    add service our_system2  
    vip address y.y.y.66  
    redundant-index 103  
    sticky-mask 255.255.0.0  
    protocol tcp  
    port 80  
    active  

!*************************** GROUP *************************** 
group VSystems  
  add service server5  
  add service server6  
  add service our_system1  
  add service our_system2  
  vip address y.y.y.66  
  redundant-index 168  
  active  

!**************************** NQL **************************** 

nql dmz_servers  
  ip address y.y.y.210 255.255.255.255  
  ip address y.y.y.211 255.255.255.255  
  ip address y.y.y.212 255.255.255.255  
  ip address y.y.y.214 255.255.255.255  
  ip address y.y.y.215 255.255.255.255 


!**************************** ACL **************************** 
acl 18  
  clause 1 deny any any destination x.x.18.248 255.255.255.255 eq ftp  
  clause 2 deny any any destination x.x.18.248 255.255.255.255 eq telnet  
  clause 3 deny any any destination x.x.18.248 255.255.255.255 eq http  
  clause 4 permit any any destination x.x.18.248 255.255.255.255  
  clause 117 permit any nql Systems_physical destination nql dmz_servers  
  clause 139 permit any x.x.18.129 eq 80 destination any  
  clause 139 permit any x.x.18.130 eq 80 destination any  
  clause 251 permit any x.x.18.248 255.255.255.255 destination any  
  clause 252 permit any x.x.18.249 255.255.255.255 destination any  
  clause 253 permit any x.x.18.254 255.255.255.255 destination any  
  clause 254 deny any any destination any  
  apply circuit-(VLAN18)  

acl 19  
  clause 10 deny any any destination y.y.y.115 255.255.255.255 eq 21  
  clause 11 deny any any destination y.y.y.115 255.255.255.255 eq 23  
  clause 12 deny any any destination y.y.y.115 255.255.255.255 eq 80  
  clause 100 permit any any destination any  
  clause 254 deny any any destination any  
  apply circuit-(VLAN19)