This might be a hard one to fix in this forum. I have an office that is very rural. we have been forced to settle for DSL.
There is a Netopia modem in pass through mode. Behind it is a cisco 831. We have had complaints from users not being able to get to certain web sites. The ISP has narrowed it down to the MTU statement on our router. We bypassed the router with one machine, and all problems were fixed. However, our network is a MPLS full mesh. The router has to stay in place. The only semi-stable MTU statement I have found is 1472. Any help will be greatly appreciated.