I have a customer in Michigan who can't access my production SaaS webserver that is hosted on Slicehost. All other companies across the US/Canada/Europe have no problem reaching the site. This problem is occuring intermittantly, and Slicehost customer service says it's a problem with the client's ISP.
I got the IP address of my client, and ping'ing that IP address from my PROD server fails, but ping'ing the IP address from my dev box or our seperate blog server (also hosted on slicehost) works. How do I debug a problem like this? I asked the client to reach out to their local ISP and ask about this problem.
A traceroute shows that the packets are getting stopped on a Comcast Michigan node which is the client's ISP. Is there anything I can do additionally to fix this problem for my client?
There is little to nothing you can do. If the ISP has a routing issue on their network that isn't allowing the connection through, then the options are:
Option 1 is usually the best course of action. Unfortunately, the Internet isn't perfect and sometimes there are connection problems. If a traceroute is showing a break within Comcast's network, then Comcast needs to fix it.
Could the isp be intercepting DNS requests ? If so, try using OpenDNS or similar services to see if any change occurs.