AS/400 port restrictions/limitations

[K Stone]

We have run into a problem with IP printers ending abnormally. We get
a TCP100D message that says "No ports available to establish a
session" I notice when I do a "wrktcpsts *cnn" command that one
printer may have several ports open. It looks like the all the
printers combined use all of the local ports available and then ends
printers to make room for more open ports. Any ideas?!
Oh, and we are on V4R3 of OS/400 (don't laugh).

[Rodney Johnson]

Adding another LAN card to your AS/400 can take care of this problem.
We have had a number of customers have to do this to handle large
numbers of remote writers.

It seems that something was introduced in V4R3 (java? http?) that
started eating up more of the ports in the 256 - 1024 range (allowed
port values for LPR...per RFC 1179). The remote writer (really LPR) has
this strange algorithm where it randomly chooses a port between 256-1024
and attempts an open. If this fails 500 times, the message TCP100D is
issued.

If you have a lot of remote writers that are actively trying to send
files (>200 usually), the TCP100D can occur rather frequently. A change
was put into the base of V4R4 to monitor for TCP100D and retry.
Course if there really are no more ports available, you remote writers
will appear to "hang" with a file in SND status instead of end.

--
Rodney A Johnson
Technical Team Lead for AS/400 Spool
Dept GJC
IBM Rochester, Minnesota

The contents of this message express only the sender's opinion.
This message does not necessarily reflect the policy or views of
my employer, IBM. All responsibility for the statements
made in this Usenet posting resides solely and completely with the
sender.

[Tom Liotta]

Can you elaborate? I read RFC1179 differently. It says:

LPR is a a TCP-based protocol. The port on which a line printer
daemon listens is 515. The source port must be in the range 721 to
731, inclusive. A line printer daemon responds to commands send to
its port.

Ports from 256 to 1024 sure shouldn't be eaten up since many are
reserved for other protocols.

Tom Liotta

[Rodney Johnson]

Tom, Caught me :-). I should have verified which RFC1179 was followed
for this feature...I believe the Revised RFC1179 had the larger port
range. I sometimes forget which parts of LPR follow the revised RFC1179
and which parts follow the original RFC1179.

Here is excerpt from revised RFC1179:

"LPR is a TCP-based protocol. The port on which a line printer daemon
listens is 515. The source port must be less than 1024. A line printer
daemon respones to commands sent to its port. The daemon may choose not
to accept the connection for several reasons:

- The source port isn't 'trusted' (in the BSD sense of being less than
1024).
- The originating host isn't permitted to use the printing facilities
provided by this host.

In these cases, the dameon sends an error message and closes the
connection."

I'm not sure, but I believe the iSeries LPR implementation may have been
derived from the OS/2 version. The larger source port range was chosen
because of the problems with not having enough source ports.

[K Stone]

Just adding a LAN card won't take of this, will it? Wouldn't you have
to assign this card an IP and then somehow divide up the resourses
(the printers) to use another LAN?

How about adding a virtual interface (IP)?

Rodney Johnson <rjoh...@rchland.ibm.com> wrote in message news:<c2a8sh$27dc$1...@news.rchland.ibm.com>...

[Rodney Johnson]

Being on V4R3, I believe you are somewhat limited. Yes just adding the
card is not enough. You have some IP configuration to do. You might
want to scan the iSeries Software Knowledge DB for a document that may
tell you how to make adding a new card work. All I know is at that
time, IBM service was telling our customers they had to add a LAN card,
another IP address, etc. I didn't get involved in it too much since the
code I support doesn't need to know or care about the configuration and
hardware stuff.

If you cannot find an article in the iSeries Software Knowledge DB, then
you might want to check on some of the red books for TCP/IP and possibly
TCP/IP configuration and reference.

Maybe if you repost your question with a different title you might get
someone's attention that has dealt with adding a new LAN card.

I guess there is one other option, and that would be to upgrade :-).

[jb]

Would he need another lan card or can another ip address be assigned to the
existing card ?
I thought that was a standard feature of IP on the as400s.

--
Jonathan.

"Rodney Johnson" <rjoh...@rchland.ibm.com> wrote in message

news:c2nlh0$1vmg$1...@news.rchland.ibm.com...

[Rodney Johnson]

From what I remember back then the customer needed another card and IP
addr. It happened just often enough that I would think there would have
been some documentation somewhere for it. Course I could be forgetting
some unique situation for that customer that may not apply to K Stone's
case. I can configure an LAN card for one IP address and mess with a few
settings and that is about the extent of my expertise with TCP/IP.
Multiple IP addresses and LAN cards and what you need to do to get more
ports is outside my expertise.

jb wrote:
> Would he need another lan card or can another ip address be assigned to the
> existing card ?
> I thought that was a standard feature of IP on the as400s.
>

--

[K Stone]

What I have found: This is an OS/400 limitation. Adding a million
LAN cards or virtual IP's will not help. We have another AS/400, so I
can set up SNA outq's to send print to the other AS/400 and have that
outq set up to IP to that printer. The AS/400 is not a heavy printer
so I can utilize its ports. SNA does not open up another port...