ACE: Overlapping alias and VIP in 2.1.6a

Answered Question
Nov 24th, 2009
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Hi,


I've just tried upgrading my ACEs from 2.1.3 to 2.1.6a (tardy I know ....) but on upgrading the first I saw that two contexts were in STANDBY_COLD and further invesigation found by sh config-error (or something like that) that it was complaining that the alias ip address on one of the VLANs clashed with the VIP IP address. I thought this had been resolved in 2.1.3 - and the Release Notes bear this out. Has this change been regressed? I didn;t upgrade the second ACE and have backed out to 2.1.3.


If I don't have an alias on the client side VLAN does it matter?  I'm looking at situation where I don't have any free IP addresses in the subnet and I'd rather not go through the hassle of changing subnets and recreating the context.


Thanks


Cathy

Correct Answer by Gilles Dufour about 7 years 4 months ago

you can run without alias address.

Especially on the frontend.

But if you are in FT mode and use the active ACE as the default gateway for the backend servers, you will need the alias to idenify the "active" ACE.


Gilles.

Correct Answer by Gilles Dufour about 7 years 4 months ago

I tested with both version A2(1.3) and A2(1.6a), you can't configure an alias ip address which is the same as a vip.



switch/Admin(config-if)# do show run class-map | i 20.122 pr 1
Generating configuration....
class-map match-all VIP-122-80
  2 match virtual-address 192.168.20.122 tcp eq www


switch/Admin(config-if)# alias 192.168.20.122 255.255.255.0
Error: Specified ip address duplicates with an existing ip address configured in the context!
switch/Admin(config-if)# do sho ver | i A2
  system:    Version A2(1.3) [build 3.0(0)A2(1.3) adbuild_22:10:16-2008/12/11_/a
uto/adbu-rel2/rel_a2_1_3_throttle/REL_3_0_0_A2_1_3]
  system image file: [LCP] disk0:c6ace-t1k9-mz.A2_1_3.bin
switch/Admin(config-if)#


So, your config is simply not valid.  But not sure how you got it running in A2(1.3).


Gilles.

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Correct Answer
Gilles Dufour Tue, 11/24/2009 - 02:30
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I tested with both version A2(1.3) and A2(1.6a), you can't configure an alias ip address which is the same as a vip.



switch/Admin(config-if)# do show run class-map | i 20.122 pr 1
Generating configuration....
class-map match-all VIP-122-80
  2 match virtual-address 192.168.20.122 tcp eq www


switch/Admin(config-if)# alias 192.168.20.122 255.255.255.0
Error: Specified ip address duplicates with an existing ip address configured in the context!
switch/Admin(config-if)# do sho ver | i A2
  system:    Version A2(1.3) [build 3.0(0)A2(1.3) adbuild_22:10:16-2008/12/11_/a
uto/adbu-rel2/rel_a2_1_3_throttle/REL_3_0_0_A2_1_3]
  system image file: [LCP] disk0:c6ace-t1k9-mz.A2_1_3.bin
switch/Admin(config-if)#


So, your config is simply not valid.  But not sure how you got it running in A2(1.3).


Gilles.

ciscocsoc Tue, 11/24/2009 - 02:55
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Thanks Gilles,


No idea why it is running as it is - possibly something to do with a migration process from an earlier code version. If it is wrong, its wrong. Am I OK to run without an alias address? I really don't want to have to change IP networks.


Thanks


Cathy

Correct Answer
Gilles Dufour Tue, 11/24/2009 - 08:45
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  • Cisco Employee,

you can run without alias address.

Especially on the frontend.

But if you are in FT mode and use the active ACE as the default gateway for the backend servers, you will need the alias to idenify the "active" ACE.


Gilles.

ciscocsoc Tue, 11/24/2009 - 08:55
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  • Silver, 250 points or more

Thanks Gilles,


I can live without the aliases in the contexts that concern me.


How do I rate your answers? I can't find the "rate this post" option even though I'm logged in.


Thanks


Cathy

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