Difference between "genmask" and "netmask"?
16,524
According to nixCraft:
Genmask : The netmask for the destination net; 255.255.255.255 for a host destination and 0.0.0.0 for the default route.
It's called 'genmask' because it shows the 'generality' (i.e. the netmask) of the route.
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Comments
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Thomas Hedley almost 2 years
In the output of
route -n
on Linux, you get something like this:Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 10.0.0.1 0.0.0.0 UG 0 0 0 eth0 10.0.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 169.254.169.254 0.0.0.0 255.255.255.255 UH 0 0 0 eth0
I know that
Genmask
refers to the netmask portion of the route, but why is it called "Genmask" instead of "netmask" like it is everywhere else? This is literally the only place I've ever seen "Genmask". -
Thomas Hedley about 9 yearsThe source of the "generality" thing seems to be the TLDP: tldp.org/LDP/nag/node75.html It's just odd that the output of
route
seems to be the only place the actual term "genmask" is used. Everywhere else it's "netmask." E.g. in my system's man files, "netmask" shows up 207 times, but "genmask" is only mentioned in theroute
man page. -
sage almost 7 yearsOne thing I like about the various unixen is that the primary tools do not typically/deliberately obscure ideas. It is sad to see this use of 'genmask' when 'netmask' would fit just as well in that output.