ASA 5510 Management Interface limitation

Answered Question
Jun 9th, 2010

Is there any known limitation to the management interface if this interface is put to work like any of the other ones? meaning for example, are there any known limitations if this interface is connected as the WAN interface for the ASA?

I have this problem too.
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Correct Answer by ddawson about 6 years 6 months ago

Yes, I'm sure.  It's called a management interface because it comes pre-configured with an IP address and a DHCP server so that you can power up a new ASA, connect a computer to that port with an Ethernet cable, and fire up ASDM to start configuring the ASA without having to do anything with the console port.  Even so, the management port is still an Ethernet port, and if you remove the "management-only" command from it you can use it just like any other interface.  One thing that's a little special about that interface, however, is that it's only a 10/100 port, even on the higher-end ASA boxes that support 4 (or more) 10/100/1000 ports, so that might limit it's usefulness.  I don't know if there are any internal hardware differences with this port compared to the others, such as bus speeds, etc., but it's still a 10/100 interface.  I've never seen nor heard of any performance issues with the Management interface, so I'd go ahead and use it if you need it and don't have a problem that it's only a 10/100 port.

HTH

Dana

CCIE #1937

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ddawson Wed, 06/09/2010 - 21:53

No, there are no limitations.  You can use it just like any of the other interface, but you have to remove the "management-only" command, of course.

insccisco Thu, 06/10/2010 - 06:53

you sure?  so why cisco called it management?

is there any link that explains the architecture of this interface?

Correct Answer
ddawson Thu, 06/10/2010 - 08:08

Yes, I'm sure.  It's called a management interface because it comes pre-configured with an IP address and a DHCP server so that you can power up a new ASA, connect a computer to that port with an Ethernet cable, and fire up ASDM to start configuring the ASA without having to do anything with the console port.  Even so, the management port is still an Ethernet port, and if you remove the "management-only" command from it you can use it just like any other interface.  One thing that's a little special about that interface, however, is that it's only a 10/100 port, even on the higher-end ASA boxes that support 4 (or more) 10/100/1000 ports, so that might limit it's usefulness.  I don't know if there are any internal hardware differences with this port compared to the others, such as bus speeds, etc., but it's still a 10/100 interface.  I've never seen nor heard of any performance issues with the Management interface, so I'd go ahead and use it if you need it and don't have a problem that it's only a 10/100 port.

HTH

Dana

CCIE #1937

insccisco Thu, 06/10/2010 - 08:43

great. just making sure to see if there are no more gotchas like this limitation of the speed regardless of whatever 5500 series model you have.

but i like to be stubborn and actually get deeper into it. i've seen many situations where improvisation can also be an evil. perhaps the hwics are good examples. i saw a situation where an 4-port hwic was purchased and the customer put one of those interfaces as a wan and they started having nightmares with reliability. i got called and engaged tac immediately to not waste anymore time and they advised that those were meant primarily as just switchports and that although you could make them L3 interfaces, at the end they were not true L3, thus the reason of the customer having lots of problems. i never really looked past that (as I do just break/fix and no time to post-mortems) but I assumed the architecture of those hwics ports werent just the same as true high speed interfaces... so perhaps the customer never really looked into the details before putting that interface as a wan interface

so when it comes to cisco i always like to respect everything they said and on this one, i was thinking if they meant the mana0/0 interface to be a "management" interface, then it is because of something.

so if there are good links that really explain the architucture of these interfaces, i'd like to read them.. i want to see those blue prints.

thanks for the input so far... I really appreciate the help

ddawson Thu, 06/10/2010 - 10:08

Well, I don't have any details on the actual hardware implementation of the Management interface, but I have been involved in probably a half dozen or so ASA installations that used that interface as a real interface (usually for Failover reasons) and I've not seen any problems.  I doubt any of these installations were pushing the limits of the ASA very hard at all so they'd be less likely to see any limitations, but since this is just a plain Ethernet port and the ASA is more similar to a standard PC architecture I'm not very concerned that any significant issues exist.  I could be wrong about that, but so far I've seen no reason to be concerned.  Out of curiosity, however, I just did a bug search at CCO and the only issues I found that mentioned the Management interface were related to IPv6 or the ASA running in Transparent mode.  So, if you're not using either of those features I suspect you'd be fine using that interface.

Good luck!

Dana

CCIE #1937

insccisco Thu, 06/10/2010 - 12:07

very good. so there we have some other stuff to be concerned if I use those features. thank you again for the input. and again, i'll go deeper and call tac to see if they can also provide more info, they usually have some links that I never find online.

john.trinh Wed, 12/09/2015 - 12:24

Hi ddawson,

I know this is a very old post, but I was wondering if you can shed to light on the mgmt port question:

If I convert it to a normal port (regular Ethernet port), will I lose my ASDM access?

Sorry if this is a sill question.

Regards,

John T

ddawson Wed, 12/09/2015 - 13:45

As long as you allow HTTP access on that interface you should be fine.  The bigger problem is that in the new generation of ASA models (all the "-X" models) you can no longer use the Management port as a regular interface - it won't allow you to remove that "management-only" command, so you can't use it to forward user data.  If you have an older ASA you should be fine, but the new ones lock down the Management port.

john.trinh Wed, 12/09/2015 - 15:37

Understood; thank you very much for your guidance ddawson!

Mine is now set to this:

ASA5510# sh run http
http server enable
http 192.168.1.0 255.255.255.0 management
http 10.10.0.0 255.255.255.0 inside
http 192.168.0.0 255.255.255.0 wifi

http 192.168.5.0 255.255.255.0 inside
http 0.0.0.0 0.0.0.0 outside

Maybe one day I'll be able to play with the -X models.

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