It is very likely it was working because you only tested from 1 IP address.
This once happened to a customer. He said he had configured NAT and it was
working before and as soon as he put another host, it didnt work anymore...


-- 
Willians Barboza
CCIE Security # 25629

2010/4/7 Tyson Scott <[email protected]>

>  That is correct Pieter-Jan
>
>
>
> Regards,
>
>
>
> Tyson Scott - CCIE #13513 R&S, Security, and SP
>
> Technical Instructor - IPexpert, Inc.
>
> Mailto: [email protected]
>
> Telephone: +1.810.326.1444, ext. 208
>
> Live Assistance, Please visit: www.ipexpert.com/chat
>
> eFax: +1.810.454.0130
>
>
>
> IPexpert is a premier provider of Self-Study Workbooks, Video on Demand,
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> CCIE (R&S, Voice, Security & Service Provider) certification(s) with
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>
>
> *From:* [email protected] [mailto:
> [email protected]] *On Behalf Of *Pieter-Jan
> Nefkens
> *Sent:* Wednesday, April 07, 2010 1:35 PM
> *To:* Brandon Carroll
> *Cc:* Kingsley Charles; [email protected]
> *Subject:* Re: [OSL | CCIE_Security] NAT with overload
>
>
>
> HI Brandon, Kings,
>
>
>
> If I remember correctly, if you do not specify overload, the first ip that
> is matched from the access-list is natted to the external address, leaving
> the other potential devices being unable to access the network. When the
> nat-timeout occurs, the global ip address becomes available again. It is
> comparible with the global pool for nat, but then with just one ip-address.
>
>
>
> E.g. nat is being applied.
>
> When using the overload keyword, pat is being used.
>
>
>
>
>
> You can compare it with the global command on the pix / asa.
>
> If you specify global (outside) 1 ip1-ip2
>
> than the first two devices accessing the network are being translated, the
> third one basically has bad luck until one of the first nat entries time
> out. Thats why I (almost) always configure a global (outside) 1 ip3 as well,
> so that PAT is occuring as well.
>
>
>
> Just a tip, if you don't know it yet.
>
>
>
> If you do a command like
>
> "ip nat inside source 123 int dialer1 overload"
>
> remember to also put a
>
> "ip nat inside source static tcp <internalipofrouter> 22 int dialer1 22
> extendable"
>
> in it as well. Otherwise you won't be able to remotely login to your DSL
> router/modem, as the dynamic nat would take presedence.
>
>
>
>
>
> I think it could even a troubleshouting item in the lab as well..
>
>
>
> HTH
>
> PIeter-Jan
>
>
>
>
>
>
>
> On 7 apr 2010, at 18:37, Brandon Carroll wrote:
>
>
>
>  Kings,
>
>
>
> I believe the IOS automatically overloads now if you don't specify.  Older
> IOS you had to use the overload command.
>
>
> Regards,
>
>
>
> Brandon Carroll - CCIE #23837
>
> Senior Technical Instructor - IPexpert
>
> Mailto: [email protected]
>
> Telephone: +1.810.326.1444
>
> Live Assistance, Please visit: www.ipexpert.com/chat
>
> eFax: +1.810.454.0130
>
>
>
> IPexpert is a premier provider of Self-Study Workbooks, Video on Demand,
> Audio Tools, Online Hardware Rental and Classroom Training for the Cisco
> CCIE (R&S, Voice, Security & Service Provider) certification(s) with
> training locations throughout the United States, Europe, South Asia and
> Australia. Be sure to visit our online communities at
> www.ipexpert.com/communities and our public website at www.ipexpert.com
>
>
>
>
>
>
>
> On Apr 7, 2010, at 9:11 AM, Kingsley Charles wrote:
>
>
>
>  Hi Brandon
>
>
>
> IOS accepts the following command without "overload" keyword. Isn't the
> following PAT?
>
>
>
> ip nat source list 123 interface g0/0
>
>
>
>
>
>
>
>
>
> With regards
>
> Kings
>
> On Wed, Apr 7, 2010 at 9:38 PM, Brandon Carroll <[email protected]>
> wrote:
>
> Overload takes you from using NAT to using PAT.
>
> Regards,
>
> Brandon Carroll - CCIE #23837
> Senior Technical Instructor - IPexpert
> Mailto: [email protected]
> Telephone: +1.810.326.1444
> Live Assistance, Please visit: www.ipexpert.com/chat
> eFax: +1.810.454.0130
>
> IPexpert is a premier provider of Self-Study Workbooks, Video on Demand,
> Audio Tools, Online Hardware Rental and Classroom Training for the Cisco
> CCIE (R&S, Voice, Security & Service Provider) certification(s) with
> training locations throughout the United States, Europe, South Asia and
> Australia. Be sure to visit our online communities at
> www.ipexpert.com/communities and our public website at www.ipexpert.com
>
>
>
>
> On Apr 7, 2010, at 9:06 AM, Kingsley Charles wrote:
>
> > Hi all
> >
> > When we configure as following, all addresses matching 123 will be
> translated to g0/0 and that is PAT. Port numbers are used to distinguish
> each hosts.
> >
> > ip nat source list 123 interface g0/0
> >
> >
> > What  does overload do?
> >
> >
> > router1(config)#ip nat source list 123 interface g0/0 ?
> >   overload  Overload an address translation
> >   vrf       Specify vrf
> >   <cr>
> >
> > router1(config)#ip nat source list 123 pool addr ?
> >   overload  Overload an address translation
> >   vrf       Specify vrf
> >   <cr>
> >
> >
> > With regards
> > Kigs
> >
>
> > _______________________________________________
> > For more information regarding industry leading CCIE Lab training, please
> visit www.ipexpert.com
>
>
>
>
>
> _______________________________________________
> For more information regarding industry leading CCIE Lab training, please
> visit www.ipexpert.com
>
>
>
> ---
>
> Nefkens Advies
>
> Enk 26
>
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>
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>
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>
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>
>
>  Think before you print.
>
>
>
>
>
>
>
> _______________________________________________
> For more information regarding industry leading CCIE Lab training, please
> visit www.ipexpert.com
>
>

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