OS specific network delay, why?

Since my new ISP installed their own router to my house(I rented a room in a student house so don't have much control on these), I started having strange delays. Any outgoing connection I do, be it http or ssh, is delayed for several seconds, and once it is established, I have no further problems. I open several simultaneous tabs in my browser and after about 5 to 8 seconds, they all connect and load simultaneously and quiet fast. I can actually play online games once I connect.What's more interesting is, I experience this only with Linux distros, namely Arch and some versions of Ubuntu. Access with Windows installs are quiet normal. What might be wrong with my router? Everything was fine with my old router but I have to use this one now.

From serverfault Atilla Filiz

• My first reaction is DNS. Check the DNS configuration of your linux systems so it's not hitting a DNS server that is down.

  From pehrs

• Two likely things, first as perhrs says, DNS.

  Second, IPv6. There's a chance that if the ISP is academic related they could have IPv6 enabled, but broken.

  You could easily be seeing a combination of this as it's been known that many bad (consumer) routers drop AAAA (IPv6) DNS queries on the floor, Windows normally won't do IPv6 lookups unless it thinks it has a working IPv6 connection.

  A way to test this would be to try host ipv6.google.com (linux) or nslookup ipv6.google.com (windows). If these requests time out you have your culprit. To work around you could use third-party DNS servers (eg, OpenDNS, Google), or your ISP's DNS servers directly. You should also request a firmware update from the ISP to fix the issue.

  Atilla Filiz : host ipv6.google.com resolves the host. No problem there. Manually setting the DNS solved the problem but I have no idea why it worked.
  From LapTop006