dns issue

For an out of town client
Client has a website that I host at his full domain and also a LMS that uses a subdomain and that is hosted elsewhere.

I can see both sites at full domains but in the clients home he can't see either

He can get to both sites via IP address, and can publish to the full domain version that I host using the IP address in Dreamweaver

If he goes through a cloaking site he can see the sites at the full domains

I checked my hosting to see if the clients IP is blocked - but no, I don't know on the LMS version but have my doubts

Both sites are long standing and the issues only started this week

Domain is at GoDaddy

When client does domain traceroute to my server it works fine.

Client has a modem provided by his IPS and then a wifi router - he replaced the router to see if that would help

ISP has remotely re-set the modem.

Client has cleaned cache on computer and power cycled the modem and router

I have suggested he ask his ISP for new IP, any other thoughts?

Regards,

David