Getting TCPIP to talk to an ADCD system.

I had a new (z/OS 2.5) ADCD system, and wanted to get FTP working. Once I had unzipped the files, and started z/OS, I could not ping or connect to the z/OS via TCPIP.

When I wanted to use z/OS on a different machine I needed to configure my laptop to give the route to the machine using and Ethernet connection

sudo ip route add 10.1.1.0/24 via 10.1.0.3 
# open a session to it
ssh -X colin@10.1.0.3 

Using my home wireless connection I could use instead

sudo ip route add 10.1.1.0/24 dev wlp4s0
# open a session to it
ssh -X colin@10.1.0.3 

The problem

I had ZD&T running on my laptop; My definitions on Linux used an IP address of 10.1.1.2, but the the shipped ADCD system has been configured for a HOME entry of 172.26.1.2.

You can either change z/OS, or you can change your Linux setup.

Changing z/OS

I wanted to get the address 10.1.1.2 on my Linux to talk to z/OS, but z/OS was not configured for this address. Using the TCPIP command NETSTAT HOME showed it was configured for a 172.26.1.2 .

In ADCD.Z25A.TCPPARMS(ZPDTDEV1) is

DEVICE PORTA MPCIPA 
 LINK ETH1 IPAQENET PORTA 
HOME &HOMEIPADDRESS1 ETH1 
BEGINRoutes 
; Destination        SubnetMask    FirstHop       LinkName    Size 
ROUTE 9.114.209.0    255.255.255.0    =            ETH1   MTU 1492 
; Destination                      First Hop      LinkName    Size 
ROUTE DEFAULT             &DEFAULTROUTEADDR        ETH1   MTU 1492 
ENDRoutes 
START PORTA 
                                                                       

The z/OS command D SYMBOLS gave

&DEFAULTROUTEADDR. = "172.26.1.1"         
&DYNXCFIPADDRESS.  = "172.26.1.20"        
&EPHEMERALPORTS.   = "10000 65534"        
&GBLRESL.          = "GBLRESOL"           
&HOMEIPADDRESS1.   = "172.26.1.2" 
&TCPPROF.          = "PROF2"                            f

Updating the address

You have several approaches.

• Update the system symbols and re-ipl or restart TCPIP
• Replace the symbols with the hard coded definitions and re-ipl or restart TCPIP
• Use system symbols and restart just the relevant bits of TCPIP
• Update the TCPIP definitions and restart just the relevant bits of TCPIP

Update the system symbols and re-ipl

See Changing z/OS system symbols is – easy – ish.

My IEASYM definition included member IEASYMAU.

I created member USER.Z25A.PARMLIB(IEASYMAU), copied member FEU.Z25A.PARMLIB(IEASYMAU) into it, and changed the definitions.

SYSDEF  SYSNAME(S0W1) 
        SYSCLONE(1A) 
        SYMDEF(&HOMEIPADDRESS1.='10.1.1.2') 
        SYMDEF(&DEFAULTROUTEADDR.='10.1.1.1') 
        SYMDEF(&DYNXCFIPADDRESS.='10.1.1.31') 
        SYMDEF(&ZCXDVIPAADDRESS.='10.1.1.32') 
        SYMDEF(&EPHEMERALPORTS.='10000 65534') 
        SYMDEF(&GBLRESL.='GBLRESAU') 
        SYMDEF(&TCPPROF='PROF2') 

I shutdown z/OS and restarted it – and then I could use PING and, once I had started FTPD, I could FTP to 10.1.1.2. If you do not want to restart z/OS see below for the long story. in Changing z/OS system symbols is – easy – ish, or “Refreshing TCP/IP definitions“, below.

Update the TCPIP definitions and restart TCPIP or re-ipl

I backed up ADCD.Z25A.TCPPARMS(ZPDTDEV1), then changed ADCD.Z25A.TCPPARMS(ZPDTDEV1) to use the hardcoded address and default router address.

Restarting TCPIP or a REIPL activated these changes – but doing this is disruptive to users.

Refreshing TCP/IP definitions.

It is not easy to refresh the TCPIP definitions. See here.

Once I had made the changes, and activated the updated definitions, I could ping to z/OS and use FTPD.

Changing Linux

I changed my devmap to have

[manager] # tap0 define network adapter (OSA) for communication with Linux
name awsosa 0022 –path=A0 –pathtype=OSD –tunnel_intf=y –tunnel_ip=172.26.1.1
device 400 osa osa –unitadd=0
device 401 osa osa –unitadd=1
device 402 osa osa –unitadd=2

The “ip route” command gave

default via 192.168.1.254 dev wlp4s0 proto dhcp metric 600
169.254.0.0/16 dev wlp4s0 scope link metric 1000
172.26.1.0/24 dev tap0 proto kernel scope link src 172.26.1.1
192.168.1.0/24 dev wlp4s0 proto kernel scope link src 192.168.1.223 metric 600

The find_io command gave

         Interface         Current          MAC     IPv4       IPv6           
 Path    Name              State            Address Address    Address        
------   ----------------  ---------------- ------- -------    --------- 
  F0     enp0s31f6         UP, NOT-RUNNING  8c:...  *          *               
  F1     wlp4s0            UP, RUNNING      d4....  192....    2a00:...  
  F2     wwan0             DOWN             a2....  *          *               
. 
  A0     tap0              UP, RUNNING      22....  172.26.1.1 fe80...
  A1     tap1              DOWN             02....  *         *               
  ...

I could ping and FTP to 172.26.1.2.