The following changes seem to have solved all urgent problems for
me:

In mosnet:db/resolv.conf

- comment out everything with a # at the beginning of each line

In mosnet:db/general.conf

Use the following lines:
TCP_SendSpace=8192
TCP_RecvSpace=16384
MBUF_CONF MaxMem=4096

Possibly you may want to increase TCP_SendSpace even further, though
this seems enough for me.