Can't access some websites

[liquidstone]

I can't open some websites on the internet, it seems that my DSL connection permits it. (sites like opera.com, speedtest.net ...)
When i connect ethernet cable with my wireless router (note this is not anymore dsl connection, but a normal ethernet), i can open all those pages. It seems that there is something wrong with the DSL in Network Connections that permits me to open some webpages.
How to fix this?

[liquidstone]

bump
ok i made video, here. with pppoeconf everything its ok, but when i manage my connection with network manager, it blocks

[DeathByDenim]

Have you check the logs to see if there are any clues there? There should be some information regarding ppp in /var/log/syslog. Any errors or warnings in there?

[liquidstone]

this is suspicious: http://pastebin.com/GgyRB1LV

[steeldriver]

I guess it might be an MTU issue - check the MTU when you are using pppoeconf and again when you are using network manager (e.g. using ifconfig), if necessary adjust the network manager MTU down

[liquidstone]

its not the MTU, its 1480

[steeldriver]

sorry, I don't understand your network configuration - you have a modem? or a router? or both? are you physically bypassing the router and connecting directly to the modem when you switch from eth to ppp?

[liquidstone]

i have wireless internet with Ubiquiti antena, attached to sort-of router. It uses ad-hoc dsl connection. I also have wireless router from who i share internet in my house. When i make connection straight from the antena, i need to make dsl connection and it's only then when i have problems. When i use my wireless router, i don't have problems

[Deorc]

I have exactly the same problem as OP said. Any suggestion?