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ip nat pools

Can anyone give me the advantage of using a nat pool, could I put an e-mail server on my pool ? or does this have to be a direct nat ?

7 REPLIES

Re: ip nat pools

Hi Carl

Normally pools are mainly used for dynamic ip assignment in that case the ip assigned to a host will not be the same and the ip from the pool will be assigned based on the availablity of the free ips in the defined pool.

So the best thing to happen for the servers which all are hosting webservices,mail,FTP etc., should be done with Static NAT to avoid any kinda discrepencies later once its put into service..

regds

New Member

Re: ip nat pools

hi there thanks for the reply, can i do a direct nat for my web server 1 to 1, or would I need to do a 1 to 1 with port numbers, is there much difference ?

Re: ip nat pools

Hi Carl

That again depends on the availability of public ips with you in your network.

If you have enough public ips to spare for different servers then you can plan for one to one natting but if you dont have enough ips to spare then better host different services using the NAT option based on the PORT numbers.(single public ip hosting different services on different port numbers natted to the induvidual server ips with the respective port numbers on which the services are hosted)

regds

New Member

Re: ip nat pools

excellent, I think im with you on that one, So basically we would only use the nat with port number option if I only have 1 ip but want to use multiple servers running different services ?, whereas if I have say 2 public ip's I could just nat my web and mail server to the 2 different public ip's ?

Re: ip nat pools

Hi Carl

You are right,if you have enough ips to spare then you can NAT them induvidually with the public ip's to private ip's of the servers which are hosting web,mail services..

regds

New Member

Re: ip nat pools

with the ip nat pool, how long is it before the entry is cleared, I gather it has a timer, say if im surfing the web the natting must remain constant, if it sees no traffic after a certain period does it release the nat ?

Re: ip nat pools

Hi Carl

Do find the different default time out values associated with the translation and also the ways to tweak the same accordingly as per our requirement..

timeout Specifies that the timeout value applies to dynamic translations except for overload translations. Default is 86,400 seconds (24 hours).

udp-timeout Specifies that the timeout value applies to the User Datagram Protocol (UDP) port. Default is 300 seconds (5 minutes).

dns-timeout Specifies that the timeout value applies to connections to the Domain Name System (DNS). Default is 60 seconds.

tcp-timeout Specifies that the timeout value applies to the TCP port. Default is 86,400 seconds (24 hours).

finrst-timeout Specifies that the timeout value applies to Finish and Reset TCP packets, which terminate a connection. Default is 60 seconds.

icmp-timeout Specifies the timeout value for Internet Control Message Protocol (ICMP) flows. Default is 60 seconds.

pptp-timeout Specifies the timeout value for NAT Point-to-Point Tunneling Protocol (PPTP) flows. Default is 86,400 seconds (24 hours).

syn-timeout Specifies the timeout value for TCP flows immediately after a synchronous transmission (SYN) message that consists of digital signals that are sent with precise clocking. The default is 60 seconds.

http://www.cisco.com/en/US/products/sw/iosswrel/ps5207/products_feature_guide09186a00801d09f0.html

regds

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