Hi Leo, My Zone Alarm is constantly blocking “a1255.g.akamai”. I did a
Google on it but didn’t find out much. Can you tell me what it is?
I had to make an assumption or two, but a few steps lead me to an answer
that I think is correct.
What I can’t explain is why Zone Alarm is blocking it.
Let me walk you through what I did. The steps may be useful in researching
other domain issues in the future.
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First off, I have to assume you really mean “a1255.g.akamai.net”. Here’s why
I say that:
“a1255.g.akamai” is an invalid domain name, simply because “.akamai” is an
invalid top level domain (TLD). Top level domains are things like “.com”,
“.net”, or country codes like “.ca”, “.nl” and so on.
My first guess, “a1255.g.akamai.com” doesn’t resolve. If, in a command
prompt, I attempt to:
I get the error message “Ping request could not find host
a1255.g.akamai.com. Please check the name and try again.”
My second guess, “a1255.g.akamai.net”, resolved properly. The ping command
responded with actual ping results.
So now, armed with a working domain name, I attempted to find out
who owns the “second level” domain, “akamai.net”.
My first attempt is to use a “Whois” service to look up the owner of the
domain. I typically start with betterwhois.com, which in this case tells me that the registrar
(not the owner) is Tucows.com, and that I need to visit them to get more
I visit Tucows domain help
site which includes their whois look-up. Entering “akamai.net” tells me what I
wanted to know: the owner is a company called, not surprisingly, “Akamai
So that didn’t help much, did it? We still don’t know what Akamai does.
To me that means it’s time for Google. Searching on “akamai” returns not
only the company home page (akamai.com), but also an interesting Wikipedia article on Akamai. In there we
learn that “Akamai Technologies … provides, among other services, global
Internet content caching.” And in one of the references cited in that article,
“Theory of how Akamai works”, we learn that there’s actually a structure to the
domain name – the “a1255” and the “g” probably mean something specific – though
we’re not quite sure what.
So what’s all that mean? What’s this “Internet content caching” thing?
To grossly oversimplify, it’s a form of web hosting that “spreads the load”
across other servers. For example, a business might use akamai to host all of
it’s images, so as to reduce load on their own servers. The akamai servers
might optimize for providing images, and only images, very quickly. For busy
sites, this type of load balancing, or more correctly, load spreading, allows
several computers, servers and infrastructure to cooperate in such a way as to
present web pages as quickly as possible.
that ‘spreads the load’ across other servers.”
While I’m not as busy as sites that use akamai, I use a similar technique
here at Ask Leo! If you download any of my podcasts, while the URL you
initially see begins with “http://ask-leo.com/podcasts/…”, that’s redirected,
and the actual download occurs from a completely different server:
“http://media.pugetsoundsoftware.com/ask-leo.com/podcasts/…”. This actually
distributes the bandwidth of the larger MP3 downloads to a completely different
server. That “media” server is acting in many ways like the Akamai service
we’ve just discussed.
Now… why is Zone Alarm tripping on it? I have no idea. You didn’t say
whether the block was outgoing or incoming. I can’t envision a reason for an
incoming connection from an akamai server, so blocking that makes
sense. But my assumption is that you’re seeing an outgoing block. Since so many
companies use Akamai services I’m not sure at all why that might be blocked,
unless the specific customer represented by “a1255.g” is something or someone
that Zone Alarm has determined may be harmful.
I’d be tempted to follow that question through with Zone Alarm.