Am having a few problems configuring the Cisco ASA5505 firewall. Have configured many routers/PC's in the past, so didnt expect this to be a problem. Hope somebody out there can help.
Our current setup is as follows:
Linksys AG241 router connected to ISP (static IP of 85.189.xxx.xxx & subnet mask 255.255.255.255 on WAN side, static IP of 220.127.116.11 & subnet mask of 255.255.255.0 on LAN side).
This is then connected to the rest of the network via a Cisco switch. All PC's connected to this switch get IP addresses via DHCP from our server in the range 18.104.22.168 - 22.214.171.124.
I have just bought an ASA5505 and placed behind the router, in front of the switch. Have configured the inside interface with a static IP of 126.96.36.199/255.0.0.0 & can connect ADSM no problem. Have also tried to configure outside interface with static IP address 85.189.xxx.xxx/255.255.255.255, however ADSM tells me that this is not a valid subnet mask for an interface. I have simply taken these details from our router 'connection status' page, so not sure what to do next?
Also have tried to add the static route to the outside interface as suggested somewhere by 'slouko'. Is this the Gateway IP as listed on our router status page as its the only IP address I can find that I do not recognise? However this appears to change periodically.
When I have sorted the above, do I then change the default gateway on all connected equipment to point to the ASA?
Lastly, are there any changes I need to make to the router to make all this work!
Thanks for any help anybody can offer, im really starting to pull my hair out!