A fix is available
APAR status
Closed as program error.
Error description
If an interface is configured with : alias4 10.xx.xx.19,255.255.0.0 alias4 10.xx.xx.36,255.255.0.0 netaddr 10.xx.xx.19 netmask 255.255.0.0 See one of alias4 is same as netaddr, cfgif will configure 10.xx.xx.19 with default mask instead if one set in netmask. netstat -i will show : en0 1500 10 <incorrect network 10.xx.xx.19 en0 1500 10.xx 10.xx.xx.36 0 0 20 20 0 ifconfig will also give wrong netmask and broadcast : en0: flags=... inet 10.xx.xx.19 netmask 0xff000000 broadcast 10.255.255.255 ==> incorrect netmask & broadcast inet 10.xx.xx.36 netmask 0xffff0000 broadcast 10.xx.255.255 Note: When this will be fixed, if one set both netaddr and alias4 with same address but with different netmasks the netmask from alias4 will prevail as it is added last and we can't get two different netmasks for same address.
Local fix
Don't add aliases with same address as original one on interfaces.
Problem summary
If chdev is used to create an alias to a network interface with the same ip address as the primary ip address, and reboot the machine, /usr/lib/methods/chgif command which is invoked at the boot time, can configure the ip address with the wrong netmask.
Problem conclusion
Modified the code of chgif to use the correct netmask while configuring an alias.
Temporary fix
Comments
APAR Information
APAR number
IV04754
Reported component name
AIX 5.3
Reported component ID
5765G0300
Reported release
530
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Submitted date
2011-08-08
Closed date
2011-08-08
Last modified date
2013-04-07
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
AIX 5.3
Fixed component ID
5765G0300
Applicable component levels
R530 PSY U844647
UP11/10/10 I 1000
PTF to Fileset Mapping
U844647 bos.net.tcp.client 5.3.12.5
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Document Information
Modified date:
07 April 2013