Need help with configuring large packet size on Solaris 7 / e6500

UNIX Solaris
1

Greetings, I'm stuck in a time warp using ancient machines from the prehistoric era that should be rightfully displayed in the Smithsonian.

We're running Solaris 7 on FDDI n/w on an E6500 host and wish to use MTU (packet size) > 1500, more like 3072 bytes to begin with and possibly up to 4096 bytes.

Linux has /etc/network/interfaces. Does ANYONE remember the equivalent in Unix? When I do ifconfig eth0 mtu 4000, I get the error SIOCSIFMTU: Invalid argument

Thanks in advance

2

You have to be sure that the network card supports frames bigger than 1500. What does this say:

ifconfig -a

PS: I've never seen eth0 interface on Solaris...

3 
hme0: flags=863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST> mtu 1500
        inet 192.168.1.2 netmask ffffff00 broadcast 192.168.1.255
hme1: flags=863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST> mtu 1500
        inet 192.168.2.2 netmask ffffff00 broadcast 192.168.2.255
nf0: flags=863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST> mtu 1500
        inet 155.84.4.17 netmask ffff8000 broadcast 135.84.127.255
nf0:1: flags=843<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
        inet 155.84.4.26 netmask ffff8000 broadcast 135.84.127.255

AFAIK, there is a config file to change the max MTU size for a device (i.e. NIC). I've seen it done in Linux and for the life of me, I can't remember how we used to handle larger packets in Solaris, as I've been away from Solaris 7 and antiquated infrastructure for over a decade now :slight_smile:

4 
# ifconfig hme0 mtu 1492

should work.

5

I can already do upto 1500 bytes in MTU size, I wish to know how to access upto 4000 bytes to take advantage of FDDI

6

so... set it to 4000. it's the same command...

7

The thing is, OP said that he needs to change MTU on FDDI NIC, which is nf0 in this case :wink: (from what I found on the Internet - http://download.oracle.com/docs/cd/E19113-01/fddi.sbus60/806-3610-11/806-3610-11.pdf\)

8

the command was an example copied from a website. i was sure that an admin can adapt the command to fit the own needs...

9

When I do ifconfig <NIC> mtu 4000, I get the error SIOCSIFMTU: Invalid argument

10

Try:

ndd -set /dev/nf instance 0
ndd -get /dev/nf \?

Post output here :wink: