On Tue, Dec 6, 2011 at 11:49 AM, Keegan Holley <keegan.holley@sungard.com> wrote:
2011/12/6 Christopher Morrow <morrowc.lists@gmail.com>
On Tue, Dec 6, 2011 at 11:16 AM, Jared Mauch <jared@puck.nether.net> wrote:
On Dec 6, 2011, at 11:07 AM, Keegan Holley wrote:
For a few years now I been wondering why more networks do not use writable SNMP. Most automation solutions actually script a login to the various equipment. This comes with extra code for different vendors, different prompts and any quirk that the developer is aware of and constant patches as new ones come up. Writable SNMP seems like an easier way to deal with scripted configuration changes as well as information gathering. Admittedly, you will have to deal with proprietary mibs and reformat the data once it's returned. Most people consider it insecure, but in reality it's no worse than any other management protocol. Yes I know netconf is better, but in most circles I'd have problems explaining what netconf is, why it's better and that I'm not making it up. So I'll take what I can get.
Some of the problems is the bulk nature of some config changes (or transactional nature on those that support atomic operations) have been harder to automate.
Anyone that has spent any quantity of time with ASN.1 generally would agree.
I recall some bay networks gear you could only program with the proper OID as the cli was basically a SNMP-SET operation on the device.
yea... same with cascade devices... icky things (both bay and cascade!)
The errors/feedback tends to be very poor over SNMP as well as you may need to walk/revisit a large number of elements to make things happen properly.
fun story/fact, you can send an snmp write to the broadcast address of a network of NT (at least, probably also post-nt versions of the OS) machines, and set their default-ttl to some arbitrary number. "Your network is too chatty... not anymore! now your internet is 5 hops across!"
Let's leave the legacy boxes out of this. Remember that SNMP bug that could keel over a cisco router? I forget the details other than the guy who wrote c code at black hat to kill routers after cisco refused to patch.
Have you had a good experience with using SNMP-Write? I have not.
long ago, in a network far away (not on the interwebs) we used snmp write to trigger a tftp config load. It worked nicely... I'm fairly certain I'd not do this on an internet connected network today though.
I can see the other comments about interactive commands and bulk read/writes, but what's the harm of doing it on internet connected boxes vs. non-internet boxes. Just about everyone uses snmp reads in the interwebs
I think the general feeling is that snmp is udp so it's spoofable and your perimeter acls will never be 100% (or rather, are you willing to risk them not being 100%?)
and as such filters it at their edges and hopefully on each platform. You'd secure it the same way you'd secure readable SNMP I assume.
read is 'painful', write can be downright deadly (to your SLAs).
Also, who tests snmp WRITE in their code? at scale? for daily operations tasks?
lol, that could be a problem.
yea, I bet the number of people that test, at scale/operations-pace, snmp WRITE is countable on a single hand.
... (didn't the snmp incident in 2002 teach us something?)
Please elaborate.
<http://www.cisco.com/warp/public/707/cisco-sa-20010227-ios-snmp-ilmi.shtml> oh, 2001... memory lag :(