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Description of problem: The busybox on RHEL5 doesn't understand "manual" method to configure a network interface, so without it, we can't use ifup to bring the interface up without assigning any IP address. IOW, ifup from busybox should support the following configuration: /etc/network/interfaces auto eth0 iface eth0 inet manual up ifconfig $IFACE 0.0.0.0 up down ifconfig $IFACE down Additional info: Upstream busybox supports this, see: http://git.busybox.net/busybox/tree/networking/ifupdown.c
I was able to up eth0 interface without assigning an address to it using busybox from RHEL5 and the following configuration in /etc/network/interfaces: auto eth0 iface eth0 inet static address 0.0.0.0 netmask 0.0.0.0 bnmask 0 State before "ifup eth0": # ip a l dev eth0 2: eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN qlen 1000 link/ether 00:1e:37:d0:50:06 brd ff:ff:ff:ff:ff:ff State after "ifup eth0": # ip a l dev eth0 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:1e:37:d0:50:06 brd ff:ff:ff:ff:ff:ff inet6 fe80::21e:37ff:fed0:5006/64 scope link tentative valid_lft forever preferred_lft forever Strace log indicates that the following commands are executed by ifup: # grep execv LOG2 | grep -v '"/bin/sh"' 4999 execve("./busybox", ["./busybox", "ifup", "eth0"], [/* 51 vars */]) = 0 5000 execve("/usr/bin/run-parts", ["run-parts", "/etc/network/if-pre-up.d"], [/* 11 vars */]) = 0 5002 execve("/sbin/ip", ["ip", "addr", "add", "0.0.0.0/0", "dev", "eth0", "label", "eth0"], [/* 11 vars */]) = 0 5003 execve("/sbin/ip", ["ip", "link", "set", "eth0", "up"], [/* 11 vars */]) = 0 5005 execve("/usr/bin/run-parts", ["run-parts", "/etc/network/if-up.d"], [/* 11 vars */]) = 0 Yes, assigning address 0.0.0.0/0 to eth0 is pointless, but apparently harmless: kernel recognizes it as a special case of "no address". I also verified that it works with upstream busybox too, and also works if busybox is configured to use "ifconfig" tool (not "ip"). If this work-around acceptable for you?
Hi, Denys, Your workaround works fine for me, thanks a lot! So we don't need this request for "manual" method now, I will leave to you to evaluate if we need to close this BZ.
BTW, I saw this error today, + ifconfig eth0 0.0.0.0 netmask 0.0.0.0 SIOCSIFNETMASK: Cannot assign requested address + exit 0
Never mind, it is my mistake...
I guess RHEL5 can live with the current situation. Closing as WONTFIX.