Firewall Wizards mailing list archives
Re: NAPT - NAT Port selection
From: Devdas Bhagat <devdas () dvb homelinux org>
Date: Sun, 22 Aug 2004 20:58:05 +0530
On 20/08/04 09:05 +0530, ravivsn () www rocsys com wrote:
Hi, NAPT devices allow access to internet by internal machines having private IP addresses using one or more public IP addresses. We are vendors of security devices and these have NAPT feature and we allow upto 63K TCP connections from internal machines at any time. 63K limit comes from number of unique source ports that can be assigned as NAT ports. Our customer, who is one of small ISPs, wanted to use these devices. This ISP gives private IP addresses to their customers and using NAPT provides
Ewwww. Public IP space is cheap. Private IP space is for end users, not ISPs.
internet access to its customers. The ISP has limited number of public IP addresses and it wants us to increase the number of TCP connection for each public IP address to go from 63K to very high number.
If they have that many customers, they can surely justify getting more public IP space. <snip>
- Is it good for NAPT device to use same NAT port for different sessions, if they are going to different destination (based on Destination IP and Port)? Do you see any problems associated with this apart one mentioned above?
Not really. All that is necessary to identify the connection uniquely is that the combination of (source port, source ip, destination port, destination ip and protocol) be unique. You may run into implementation issues, tracking all these connections. Devdas Bhagat _______________________________________________ firewall-wizards mailing list firewall-wizards () honor icsalabs com http://honor.icsalabs.com/mailman/listinfo/firewall-wizards
Current thread:
- NAPT - NAT Port selection ravivsn (Aug 20)
- RE: NAPT - NAT Port selection Bill Royds (Aug 20)
- RE: NAPT - NAT Port selection Orca (Aug 22)
- Re: NAPT - NAT Port selection Srini (Aug 22)
- VPN endpoints hermit921 (Aug 25)
- Re: VPN endpoints Kevin Sheldrake (Aug 26)
- Re: VPN endpoints Mason Schmitt (Aug 26)
- VPN endpoints hermit921 (Aug 25)
- Re: NAPT - NAT Port selection Devdas Bhagat (Aug 22)
- Re: NAPT - NAT Port selection Harald Welte (Aug 25)