Re^2: Pinging network devices and setting SNMP traps

On some networks they are filtered; so you cannot get a response

ICMP filtering is not as common-place as it was say 2-3 years ago. There was one particular worm (can't recall exactly which one.. MSBlaster, perhaps?) that used an ICMP probe to search for vulnerable hosts. It caused havoc for a short time, and many ISP's started filtering ICMP in response. The problem with ICMP filtering is that it can have unwanted side-effects, such as breaking Path MTU Discovery - and so many of these filters have gradually been removed.

In my experience, most ISP's will will remove an ICMP filter, or at least allow it for a specific host - if asked nicely.

Cheers,
Darren :)

Comment on Re^2: Pinging network devices and setting SNMP traps

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Re^3: Pinging network devices and setting SNMP traps by Herkum (Parson) on Jul 13, 2006 at 16:22 UTC
most ISP's will will remove an ICMP filter That is assuming that you are working with an ISP; large business tend to have their own network staff. God forbid they don't have anyone looking over them, if that is the case you will end up with a monster because most of them will implement any security idea they read in magazine. They end up making the whole thing so complicated they don't even know how it all works; it is like spaghetti code with network devices. I am not fond of our networking staff, can you tell... :)	[reply]
Re^4: Pinging network devices and setting SNMP traps by roboticus (Chancellor) on Jul 14, 2006 at 19:11 UTC
Herkum: I had no idea you worked at the same company as me! Seriously, though, this is my first gig at a Fortune 500 company, and I am amazed by the networking and security configurations. Quite frightful. I would tell you where I worked, except that I'd hate to get fired. About all I could tell you is that it's a Bank, somewhere in America... --roboticus	[reply]