I as network administrator very much dislike how network masks (hexadecimal format) are show for IPv4 by ifconfig. Since this i added the '-D' switch and some code allowing ifconfig to print IPv4 netmasks in CIDR format. As an example: Original behaviour: [18:25][db][~corebug/ifconfig_my] # ./ifconfig LAN LAN: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500 options=3<RXCSUM,TXCSUM> ether 00:12:79:d2:e4:7d inet 192.168.0.4 netmask 0xffffff00 broadcast 192.168.0.255 inet6 fe80::212:79ff:fed2:e47d%LAN prefixlen 64 scopeid 0x9 nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL> media: Ethernet autoselect (100baseTX <full-duplex>) status: active vlan: 10 parent interface: bge0 Behaviour with '-D' switch: [18:25][db][~corebug/ifconfig_my] # ./ifconfig -D LAN LAN: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500 options=3<RXCSUM,TXCSUM> ether 00:12:79:d2:e4:7d inet 192.168.0.4/24 inet6 fe80::212:79ff:fed2:e47d%LAN prefixlen 64 scopeid 0x9 nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL> media: Ethernet autoselect (100baseTX <full-duplex>) status: active vlan: 10 parent interface: bge0 Note the difference between inet 192.168.0.4 netmask 0xffffff00 broadcast 192.168.0.255 and inet 192.168.0.4/24 I think that such a switch must be present and i suppose that lot of ISP and/or enterprise network admins would agree with me. Files affected are: ifconfig.c, ifconfig.h, af_inet.c. The diff between original version and my one is included Fix: Patch attached with submission follows: How-To-Repeat: Just build the ifconfig:)
A commit references this bug: Author: allanjude Date: Tue May 31 17:30:08 UTC 2016 New revision: 301059 URL: https://svnweb.freebsd.org/changeset/base/301059 Log: ifconfig(8) now supports some output formatting options specified by the -f flag or IFCONFIG_FORMAT environment variable, the user can request that inet4 subnet masks be printed in CIDR or dotted-quad notation, in addition to the traditional hex output. inet6 prefixes can be printed in CIDR as well. For more documentation see the ifconfig(8) man page. PR: 169072 Requested by: seanc, marcel, brd, many others Reviewed by: gnn, jhb (earlier version) Relnotes: yes Sponsored by: ScaleEngine Inc. Differential Revision: https://reviews.freebsd.org/D2856 Changes: head/sbin/ifconfig/af_inet.c head/sbin/ifconfig/af_inet6.c head/sbin/ifconfig/af_link.c head/sbin/ifconfig/ifconfig.8 head/sbin/ifconfig/ifconfig.c
You can now select between hex, dotted (255.255.255.0), and CIDR (/24) like so: ifconfig -f inet:dotted or set IFCONFIG_FORMAT=inet:cidr