Subnetmask UX10.20, first-last subnet

[Wilko Sruebner]

Why can`t I use the first and the last subnet within a subnetmask with HP UX
10.20?
With UX 09.05 it was possible. Is there any RFC with the rule, that the first
and last subnet should not be used?

[Jim Butler_4]

In 10.20 - Have you installed any patches? I remember a long time ago I had a
similar problem on HP 1020 because the OS was sticking like glue to RFC1122. I
think HP came out with a patch to rectify and free up the problem (you had to
mask the addresses with the proper mask within a class address) i.e. a class A
address needed to have a class A subnet, a class B address needed a class B
subnet, etc..... (Check the inet patches)

You should not use a mask that has a 0 or 255 in the last octet, which by the
sounds of it is what you are attempting. (think of it as 255 being the
broadcast, and 0 is the response)

Otherwise, you should be able to use any subnet mask you want.

[Sharif Naser_2]

1> install the latest hp-ux 10.x arpa transport cumulative patch.
2> create a text file called nettune_script with the following line:
/usr/contrib/bin/nettune -s ip_ckeck_subnet_addr 0
3> mv nettune_script /sbin/init.d
4> chmod 555 /sbin/init.d/nettune_script
5> chown bin:bin /sbin/init.d/nettune_script
6> cd /sbin/rc2.d
7> ln -s /sbin/init.d/nettune_script \ /sbin/rc2.d/S006subnet
8> reboot or /sbin/init.d/net stop and then start