folkert/simh-testsetgenerator
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

slirp: Describe NAT limitations in the attach help

Browse source
This commit is contained in:
Mark Pizzolato 2015-10-29 05:06:01 -07:00
parent 7266304105
commit 1d0a3b4402
1 changed files with 24 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

25
slirp_glue/sim_slirp.c
View file

@ -404,7 +404,30 @@ fprintf (st, "%s",
" NODHCP disables DHCP server\n"
"Default NAT Options: GATEWAY=10.0.2.2, masklen=24(netmask is 255.255.255.0)\n"
" DHCP=10.0.2.15, NAMESERVER=10.0.2.3\n"
" Nameserver defaults to proxy traffic to host system's active nameserver\n"
" Nameserver defaults to proxy traffic to host system's active nameserver\n\n"
"NAT limitations\n\n"
"There are four limitations of NAT mode which users should be aware of:\n\n"
" 1) ICMP protocol limitations:\n"
" Some frequently used network debugging tools (e.g. ping or tracerouting)\n"
" rely on the ICMP protocol for sending/receiving messages. While some\n"
" ICMP support is available on some hosts (ping may or may not work),\n"
" some other tools may not work reliably.\n\n"
" 2) Receiving of UDP broadcasts is not reliable:\n"
" The guest does not reliably receive broadcasts, since, in order to save\n"
" resources, it only listens for a certain amount of time after the guest\n"
" has sent UDP data on a particular port.\n\n"
" 3) Protocols such as GRE, DECnet, LAT and Clustering are unsupported:\n"
" Protocols other than TCP and UDP are not supported.\n\n"
" 4) Forwarding host ports < 1024 impossible:\n"
" On Unix-based hosts (e.g. Linux, Solaris, Mac OS X) it is not possible\n"
" to bind to ports below 1024 from applications that are not run by root.\n"
" As a result, if you try to configure such a port forwarding, the attach\n"
" will fail.\n\n"
"These limitations normally don't affect standard network use. But the\n"
"presence of NAT has also subtle effects that may interfere with protocols\n"
"that are normally working. One example is NFS, where the server is often\n"
"configured to refuse connections from non-privileged ports (i.e. ports not\n"
" below 1024).\n"
);
return SCPE_OK;
}