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December 15, 2017

Making a 3000 respond to networks, faster

I have a new HP 3000 A-500 installation that I can't Telnet to. Ping works both ways, but I get nothing with Reflection's Telnet. What do I need to check on the 3000 to get Telnet running?

Robert Schlosser says:

Two things come to mind: Check if the JINETD job is running [run it by streaming JINETD.NET.SYS]; and if the line "telnet 23/tcp" is in your SERVICES.NET.SYS file.

Donna Hofmeister adds:

You also need to have INETDCNF.NET configured.

There's a collection of 'samp' files in .NET that in most cases need to be copied to their 'real' file name in order to make TCP/INETD networking work.

Hofmeister, one of the community's more experienced hands with the standard Unix and Posix utilities built into MPE/iX and the HP 3000, explains.

The samp files are 

BPTABSMP -- bootptab (most people don’t use)
HOSTSAMP -- hosts
INCNFSMP -- inetd configuration
INSECSMP -- inetd security 
NETSAMP  -- reachable networks
NSSWSAMP -- nsswitch
PROTSAMP -- protocol
RSLVSAMP -- DNS resolving
SERVSAMP -- services

I believe each of the files also has a counterpart in /etc which is a link to the real file in .NET.SYS. If the real files are missing from .NET.SYS then many things (including Telnet and FTP) won’t work.
Our N-Class response times have slipped into unusable measurements. Linkcontrol only shows an issue with Recv dropped: addr on one path. Our enterprise network monitoring software sends a packet that the HP 3000 cannot handle. Do I need to shutdown and restart JINETD or restart the network to have my TCP changes in NMMGR take effect?

Craig Lalley wonders:

How are your gateways defined? If you change the gateway

NSCONTROL ;UPDATE=INTERNET

then you could try deleting the wrong gateway and see if it helps. You may have a router broadcasting a wrong gateway.

Hofmeister says the problems might be in the physical layer:

Did you change NMMGR before or after the reboot? If after, you're going to want to reboot again. Your packet loss is disturbing. I'd be suspicious of a physical layer problem.

Problems in the physical layer can be addressed by replacing parts, Mark Landin advises.

  • Could be a bad network cable or connector. Replace them.
    Could be a bad network switch port. Connect the system to another port (properly configured, of course).
  • Could be a bad NIC. Swap them in the 3000 and see if the problem moves with the card.

Hofmeister points back to TCP timer issues"

On PCI (A- and N-Class) systems with 100bt cards, you're more likely to see 'recv dropped: addr' counts due to the way the card handles (or not, actually) traffic routed for a different destination.

Typically these counts are nothing to be concerned about. What is concerning are the TCP statistics.  Retransmits are almost always a function of using the default (or otherwise messed up) TCP timers.

08:23 PM in Hidden Value | Permalink

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