FTP and PPTP in diferent servers behind NAT

Aug 03, 2006 3 Replies
FTP and PPTP in diferent servers behind NAT open original image

Hi,



i'm trying to setup an 827 (12.2(8)) router with the following scenario :



-all the PPTP related traffic in the inside global interface must be sent to the VPN server in the server1 in the inside local lan.



-all the FTP (and others like www,mail...) related traffic in the inside global interface must be sent to the DMZ server in the server2 in the inside local lan.



The only way i found to map gre protocol to the internal server is assign all the traffic to it, with an entry like (TCP 1723 is no problem with an static entry) :



ip nat inside source static server1ip globalip



So anyone knows if is possible to send ONLY the gre traffic to a determinate host ?



I ask that because the normal behaviour would be that the "default server" was the server2 (because it offers all the services but VPN). Additionally, i have not found a way to specify a port range in the ip nat , so passive ftp connections are not working correctly (write manually or automagically 64000 rules one per port is not an option, neither modify the port range in the ftp server).



So, if no way to redirect only gre, is it possible to redirect non privileged ports (>1023) to server1 avoiding to write lots of lines like :



ip nat inside source static tcp server2ip 1024 interface ATM0.1 1024



I know that in acl is possible to do a gt 1023, but how to apply to ip nat ... !


In the actual situation, if i do :



ip nat inside source static server1ip globalip the VPN works correctly but passive FTP does not



and if i do



ip nat inside source static server2ip globalip the passive FTP works correctly but ovbiously PPTP does not



so any hint ?



Thanks in advance ..



Make sure the IOS version you are using supports the "NAT-Support for PPTP in an Overload (Port Address Translation) Configuration " feature

see

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also see "Configuring PPTP Through PAT to a Microsoft PPTP Server":

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so, that means that from 12.1(4)T, gre is implicitly redirected to the same host when 1723 TCP is ...

I'm going to try ...

Thank you very much !!

I think what it means is that Cisco is creating a separate NAT translation entry ( actuall PAT entry) for each GRE session. I assume they are using the GRE PPTP peer call id to identify the session ; wild guess on my part.

I am not sure which end initiated the opening of the GRE tunnel so you may need to ensure that you inbound access list allows GRE.

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