I think the old McBooks from about 10 years ago are just marvelous. It’s not like the today’s “crap” where you have no possibility to replace the RAM or the hardisk because they are soldered: It is really a pitty that Apple moved away from providing any repairable Hardware!
The problem was however that I did not get any OS/X software updates any more and more and more of my needed functionality stopped to work.
So I finally decided to install Linux and everything was working as expected except this one thing: I could not login to Github or Skype, but most other web sites were working w/o any issues.
I was clueless where to look for a solution until I decided to access the Internet via my mobile phone and to my big surprise everything was working that way.
So it must be my router – I thought – and I replaced it with an old AirPort – but I ended up with the same problem!
I was installing docker, but here as well, the download of an image did not work and was giving some strange error message: But here Google was helping and I found the proposal to set the MTU to a smaller value.
So I double checked my network settings, and indeed there was an option to set the MTU. I changed the proposed value from ‘automatic’ to 1000 and suddenly everything started to work!
And finally I have now a working Development Laptop again with actual software versions!