setting MTU Size to 1430

[Roland Rebstock_1]

I need to set my mtu size to 1430, I've updated the netconf file and rebooted the server. Does this look correct? Were installing encrypted links between checkpoint firewalls and my mtu must be 1430..

[G. Vrijhoeven]

Hi Roland,

The Pmtu field applies only to host routes. The Pmtu field for network and default routes is the same as the MTU of the network interface used for the route.

In your case the pmtu of the default route is 1430.

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B2355-90128/B2355-90128_top.html&con=/hpux/onlinedocs/B2355-90128/00/01/197-con.html&toc=/hpux/onlinedocs/B2355-90128/00/01/197-toc.html&searchterms=1m%7cnetstat&queryid=20040419-120321

HTH,

Gideon

[G. Vrijhoeven]

Sorry,

To change the PMTU of lan3 you can usethe lanadmin command:
-m Display the current MTU size of the interface corresponding to PPA.
-M mtu_size Set the new MTU size of the interface corresponding to PPA. The mtu_size value must be within the link specific range. You must have superuser privileges.

You could check these links:

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=516449

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=127437HTH,

Gideon

[Roland Rebstock_1]

How do I set the interface to 1430 so a reboot wont switch it back to 1500? I have the routes using route_args="-p 1430" in the netconf but dont see how to set the interface permanently

[RAC_1]

You can not put it in /etc/rc.config.d/netconf file.

You will have to write a script and put it in /sbin/init.d/ and appropriate links in /sbin/rc?.d/ directories.

Make sure you use unuses start and kill nos in /sbin/rc?./d directories.

Anil

[G. Vrijhoeven]

Hi,

I did not know how to alter the MTU size permanently, so i did a search. I found the next links. It explains how you can set up Jumbo Frames ( only supported by gbit interfaces but that is >1500 10000) You do not want this settings but it might help you to configure your interface.

MTU (Maximum Transmission Unit): Jumbo Frames
Optional
1500 bytes
SAM or edit /etc/rc.config.d/hpietherconf or temporarily: lanadmin -M
lanadmin -M
9000 ppa# (see Note 3 below)

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/A7011-96001/A7011-96001_top.html&con=/hpux/onlinedocs/A7011-96001/00/00/11-con.html&toc=/hpux/onlinedocs/A7011-96001/00/00/11-toc.html&searchterms=hpietherconf&queryid=20040419-125517

edit the following configuration file using an editor such as "vi":
/etc/rc.config.d/hpietherconf.
Set the mtusize by editing HP_IETHER_MTU[0]=mtusize, and insert the proper interface name: HP_IETHER_INTERFACE_NAME. When the system reboots, the interface will be configured for jumbo frame operation.

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/A7011-96001/A7011-96001_top.html&con=/hpux/onlinedocs/A7011-96001/00/00/12-con.html&toc=/hpux/onlinedocs/A7011-96001/00/00/12-toc.html&searchterms=MTU%7cnetconf&queryid=20040419-125303

HTH,

Gideon

[RAC_1]

http://www5.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000062910454

Anil