SUMMARY -number of logical interfaces

From: Mark Conroy (
Date: Thu Jul 01 1999 - 09:21:17 CDT

To the group,

Many thanks to all of the people who took the time to respond - I really
appreciate it. I hope I didn't miss anyone.

Darren Dunham
Frank Smith
Timothy Lorenc
Mark Sherman
Darren Dunham
Carl Carpenter
Mike Allman
Bill Hathaway
Horacio Lopez Padilla
John Weekley
Tobias Wahlgren

All of the responses indicated that you can have up to 255 logical addresses per
interface by for Solaris 2.5 and it is the default for Solaris 2.6. there is a
kernel parameter that can be set with ndd that can increase the number to 8181.

Bill Hathaway mentioned:

ndd -set /dev/ip ip_addrs_per_if 8192
in one of the early rc scripts, before the interfaces are brought up.

or you could probably use
set ip:ip_addrs_per_if=8192
in /etc/system

which might be a cleaner approach

Mike Allman indicated that 255 was the limit on Solaris 2.5 and the default on
Solaris 2.6

Sun 's web site has a document called infodoc 15659 that contains all of the

Horacio Lopez Padilla indicated that:

Check the solaris 2.X FAQ:

Question 4.10:

4.10) How can I have multiple addresses per interface?

Solaris 2.x provides a feature in ifconfig that allows having more than
one IP address per interfaces. Undocumented
but existing prior to 2.5, documented in 2.5 and later.


        ifconfig IF:N ip-address up

where "IF" is an interface (e.g., le0) and N is a number between 1 and
<MAX>. Removing the pseudo interface and
associated address is done with "ifconfig IF:N down".

As with physical interfaces, all you need to do is make the appropriate
/etc/hostname.IF:X file.

The maximum number of virtual interfaces, <MAX> above, is 255 in Solaris
releases prior to 2.6. Solaris 2.6 and
Solaris 2.5.1 with the Solaris Internet Server Supplement (SISS) allow you
to set this value with ndd, upto a hard
maximum of 8192.

/usr/sbin/ndd -set /dev/ip ip_addrs_per_if 4000

There's no limit inspired by the code; so if you bring out adb you can
increase the maximum even further.


         Horacio Lopez Padilla
    Soporte Tecnico/Technical Support

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