troubleshooting Question

Cisco, ASA, 5505

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turtle1296 asked on
Hardware FirewallsCisco
13 Comments1 Solution2544 ViewsLast Modified:
Hi experts,

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 & subnet mask on WAN side, static IP of & subnet mask of 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 -

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 & can connect ADSM no problem.  Have also tried to configure outside interface with static IP address, 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!
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