Question : Subnet mask confusion on a cisco 1841 box

Hi all-

Heres my situation - I am replacing an Actiontec DSL router with a Cisco 1841 box that has an ADSL wan card in it.

Everything is working fine, except I dont trust what I have had to do to get IP up over the wan port, and as such I think its breaking my IPsec tunnels.  But before that, heres whats going on-

I have a static IP from my ISP.  It works either via DHCP or statically addressed.  Via DHCP the actiontec was recieving a 63.x.x.x/32 address.  The 32 bit subnet has me worried, in that the cisco box would not accept that from DHCP, nor would it let me hard configure the box that way.  This may be a limitation of the gui interface though - I may have to console in to make that command work, I dont know.  But, anytime I tried assigning that ip/sub mask via the gui, it complained about an invalid IP or sub mask.  

So, my solution - I wasnt sure if the actiontex was even reporting the subnet mask to me properly - so I changed it to a 24 bit subnet mask.  That worked perfectly, in terms of getting the wan connection up!  But, I have a few ipsec tunnels that sync, encryption is working, but IP wont bind to the tunnels.  I suspect this problem is the mask, and what I want to know is-

Is the 32 sub mask valid in theory?  And if so, then it looks like the cisco gui is screwing me up, and it would be great to get some pointers as to the syntax of the console commands to delete the old mask and add a new one.

If it's not valid, I think I need to talk to my ISP and see if someone on thier end screwed me up.  I may call them up anyhow, just to double check.

Sub question for bonus points - I want to forward port 80 to my web server, but I dont want to break the gui config tool on the router - do I need to do anything special to get that done, IE reconfig that gui to port 81?  I dont see anything on the gui to do that, but it is big.

Max points on this one!  Feel free to ask me any other questions to clarify any of the above.

Also, theres a tool I found online here:
http://www.networkclue.com/routing/tcpip/calculating-masks.aspx#
its linked about halfway down, titled "subnet mask calculator" and insists that my sub mask is not going to work real well at 32 bits.  Thats what I thought too. Its been a few years since I was in the networking field, all this is fuzzy to me at best.  Any and all help appreciated!

Thanks!

Eric

Answer : Subnet mask confusion on a cisco 1841 box

>>Is the 32 sub mask valid in theory?

No.  This would be a network with no valid IP's on it.  However I have the same mask (255.255.255.255) used when receiving an IP via PPTP.