Post by markI set up internal network.
Connect Mint and Ubuntu and Windows.
Now, when I send one big file from OS to another OS it works.
But, when I send alot small files, transfer start and after minute hang
and latter stop.
Why is that?
Makes no particular sense.
*******
Fire up Wireshark and capture a trace.
See if it's doing Path MTU, or it is looking for
and not finding a "gateway". Basically, the last
packets in your trace, should hint at where the
protocol stopped and dropped dead. Maybe it's
requesting to "discover something" and that something
never responds, because it does not exist.
There's no DNS in there nor DHCP. When I tested
that "internal network", it was more aggravation than
I was able to put up with.
*******
There is TCP and UDP. TCP uses a reliable three-packet
protocol and is "unstoppable". An error message should
always result. That's what is unstoppable about it.
UDP is a single packet thing, where the developer designs
any necessary reliability features on top of the basic transport.
UDP is excellent on a LAN, because the odds of packet
loss are relatively low, and the overhead is lower. If
for some reason, you designed a file transfer program to
use UDP, there were no retries or timers, the protocol
might easily drop dead. All it would take is one lost
UDP packet, for it to drop dead.
For file transfer, TCP is an excellent choice - if the
protocol is failing, there should be an error message of
some sort. "Destination unreachable". That sort of thing.
However, TCP does have one failure case. Black hole routing.
Differences in MTU size, the need to discover the minimum
MTU to make a path work. On a home LAN, the MTU is normally
about 1500 bytes. If a user, uses a VPN, the MTU is typically
smaller, and then it may be necessary to use path discovery.
Path discovery requires some portion of ICMP to be working.
I have seen this with my ISP and their email server - I would
send a message slightly bigger than 1500 bytes, the transfer
would stop, no error message would appear. The two machines
(my client, the email server) will happily sit there all day
long, with the unused ends of the connection still lashed up.
The email server had a lower MTU than normal, plus the twits
had entirely disabled ICMP, not just the ping part of it.
https://blog.cloudflare.com/path-mtu-discovery-in-practice/
There are workarounds for that.
In any case, get your Wireshark working and check out
what protocol thing is going on, before the LAN drops
to "silence".
Paul