I made a bit of progress in rolling out my own PING server and even an ARP server for DOS as a TSR and I use DOSBOX for testing but its not working well. I'll break my problem down into a few parts because I'm now thinking its a driver/dosbox issue more than anything else.

The main problem

When I run my ping server, I run tests with the linux ping tool. If I dont run a networking tool, then my TSR runs fine and DOSBOX runs normal.

If I make ping send a small set of data of under 2000-ish bytes, to the server in DOSBOX, it runs fine and the data is collected at the server end once in one piece and I do not notice a slowdown.

BUT. if I send a relatively large amount of data in one go (between about 4000 to 6000-ish bytes), the server (based on my observations) is forced to collect the data at a high speed in multiple pieces, and eventually this will cause DOSBOX to crash even if after I stop the linux ping program.

My driver/linux/dosbox setup

I followed a method similar to this:
https://www.dosbox.com/wiki/Slip_configuration_on_linux_host

This is my linux script to start DOSBOX:

1#!/bin/bash
2#turn on IP forwarding
3echo 1 > /proc/sys/net/ipv4/ip_forward
4#setup tcp port
5socat -4 PTY,link="/tmp/dbnet",raw,echo=0 TCP4-LISTEN:8001 &
6sleep 1
7#convert port to high speed serial line
8slattach -v -s 115200 -p adaptive "/tmp/dbnet" &
9sleep 1
10#setup IP address
11ifconfig sl0 192.168.7.1 dstaddr 192.168.7.2 netmask 255.255.255.252 mtu 1524 txqueuelen 15240 up 
12#flush nat tables (I have nothing else in them)
13iptables -t nat -F
14#add ip as masquerade
15iptables -t nat -A POSTROUTING -s 192.168.7.0/30 -j MASQUERADE
16#run dosbox
17dosbox

and this is my serial line in dosbox config:

1serial2=nullmodem server:127.0.0.1 port:8001 transparent:1

And I use this in my DOSBOX autoexec.bat to load the packet driver on startup and I get a MAC address (not FF:FF:FF:FF:FF:FF). So I thought my network setup is good unless I'm doing something wrong.

1ethersl -p 0x60 3 0x2F8 115200

Before I fret further about my code, am I taking the wrong steps to make networking efficient in a DOSBOX environment? Could I do something better like change the linux utilities that I should load and/or the packet driver program in DOS from within DOSBOX?