Re: Static NAT Redundancy with HSRP

From: Gregory Gombas (ggombas@gmail.com)
Date: Tue Nov 06 2007 - 13:00:17 ART


I'm not sure I follow?

Let me restate the question and I hope Narbik himself can chime in here.
There seem to be three different ways to configure NAT redundancy:

Scenario 1 - Static NAT with HSRP:
Step 1. Configure HSRP groups named HSRP-1
Step 2. Tie the group name to the static command as follows:
Ip nat inside source static 10.1.123.1 192.1.1.1 redundancy HSRP-1

Scenario 2 - Stateful NAT with HSRP:
Step 1. Configure HSRP groups named HSRP-1
Step 2. Tie the group name to the stateful NAT configuration as follows:
Router 2:
ip nat Stateful id 1
redundancy HSRP-1
mapping-id 10
Router 3:
ip nat Stateful id 2
redundancy HSRP-1
mapping-id 10

Scenario 3 - Stateful NAT without HSRP (Primary/Backup):
PRIMARY:
ip nat Stateful id 1
primary 10.88.194.17
peer 10.88.194.18
mapping-id 10
BACKUP
ip nat Stateful id 2
backup 10.88.194.18
peer 10.88.194.17
mapping-id 10

My questions is what is the first scenario for? What is the
significance of the redundacy keyword? How does it tie in with the
HSRP config?
How does that differ from configuring the two routers with static NAT
and no redundancy keyword????

On 11/6/07, Victor Cappuccio <vcappuccio@gmail.com> wrote:
> Hi Gregory,
> I had in CANTV this same issue, checking my old emails I found that
> probably this link could help a lot
> http://www.cisco.com/en/US/products/sw/iosswrel/ps1839/products_white_paper0900aecd8052870b.shtml
> Also:
> http://www.iphelp.ru/faq/29/cisconut2-CHP-13-SECT-3.html
> http://www.cisco.com/en/US/docs/ios/12_3/ipaddr/command/reference/ip1_i2g.html#wp1079180
> http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t/122t4/ftnthsrp.htm
>
> Also be aware that CPU Process utilization and memory is critical in this
> situation, using the using the following TCL Script to capture the number
> of translations and using the show ip nat statistics to determine the
> number of dynamic entries created in the NAT tables such as in: Active as to
> Standby
>
> proc SNAT { DURANTE interval } {
> set end [expr [clock seconds] + $DURANTE]
> set cur [clock seconds]
> set interval "${INTEVALO}000"
> while { $cur < $end } {
> show clock
> show IP NAT sta | inc To
> show proc cpu | exc 0.00
> show memory statistics
> puts "\n"
> after $TIEMPO
> set cur [clock seconds]
> }
> }
>
> My 2 cents
>
> Victor Cappuccio
> www.vcappuccio.wordpress.com
>
>
> On Nov 6, 2007 3:51 PM, Gregory Gombas <ggombas@gmail.com> wrote:
> >
> > Can someone please explain what the redundancy keyword at the end of a
> > static nat statement does? For example:
> >
> > Ip nat inside source static 10.1.123.1 192.1.1.1 redundancy HSRP-1
> >
> > We tried the configuration from Narkbik's NAT lab excercise #9, and we
> > found that failover worked the same with or without the redundancy
> > keyword:
> >
> > Ip nat inside source static 10.1.123.1 192.1.1.1
> >
> > Here is the relevant configuration:
> >
> > On R2
> > interface FastEthernet0/0
> > Standby 1 ip 10.1.123.100
> > Standby 1 priority 110
> > Standby 1 preempt
> > Standby 1 name HSRP-1
> > Standby 1 track FastEthernet0/1 50
> > ip nat inside
> >
> > interface FastEthernet0/1
> > Standby 2 ip 200.1.1.100
> > Standby 2 priority 110
> > Standby 2 preempt
> > Standby 2 track FastEthernet0/0 50
> > ip nat outside
> >
> > Ip nat inside source static 10.1.123.1 192.1.1.1 redundancy HSRP-1
> >
> >
> > On R3
> > Interface FastEthernet0/0
> > Standby 1 ip 10.1.123.100
> > Standby 1 preempt
> > Standby 1 name HSRP-1
> > ip nat inside
> >
> > Interface FastEthernet0/1
> > Standby 2 ip 200.1.1.100
> > Standby 2 priority 100
> > Standby 2 preempt
> > ip nat outside
> >
> > Ip nat inside source static 10.1.123.1 192.1.1.1 redundancy HSRP-1
> >
> >
> _______________________________________________________________________
> > Subscription information may be found at:
> > http://www.groupstudy.com/list/CCIELab.html
> >
>
>
>
> --



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