[UPHPU] access server in Utah from Singapore

[Lonnie Olson]

Brandon Stout wrote:
> Daniel C. wrote:
>> On 1/18/07, Brandon Stout <bms at mscis.org> wrote:
>>>   traceroute msn.com
>> Tracing route to msn.com [207.68.172.246]
>> over a maximum of 30 hops:
>>
>> <snip lots of hops that work fine>
>>
>> 12     *       18 ms     *     74.40.3.150
>> 13     *        *        *     Request timed out.
>> 14     *        *        *     Request timed out.
>>
>> <snip a handfull of hops that timed out>
>>
>> This still gives us some information - the traceroute starts to die at
>> 74.40.3.150.  Surely this is useful information?  I used to use
>> traceroute to troubleshoot network connections all the time.
> 
> Daniel,
> 
> Not terribly useful information since MSN.com works just fine for web,
> email, telnet, and ssh.  That tells us that some server(s) from hop 13
> block icmp, and that's it.

Actually, it is useful.  It confirms connectivity to 74.40.3.150.  This 
means that there is not a problem with your link, your upstream 
provider, etc.  This information is very useful.

Also, This blocking of ICMP traffic is *not* common.  MSN is an 
exception, not the rule.  All of the major backbone providers do not 
block ICMP.  Most ISPs do not block ICMP.  The majority of the ICMP 
blockers are individual corporate networks, and their internal network 
structure is not important, nor useful, to you.

--lonnie