Why does ifupdown2 does not remove old entries?

[dandud100]

Hello, I am using ifupdown2 on my Proxmox but I found out, that if I remove something in my interfaces.new and append it, it will not remove it from my iptables. I ran iptables-save to see this.

Is this normal behavior? It is so annoying to remove the not needed bridges by myself. Also I need to restart my server to get this applied.

[julienfortin]

Hi @dandud100

Can you show clarify your request by showing example of your configuration, commands that you are running and old entries not removed?

Thanks

[dandud100]

Hi @dandud100

Can you show clarify your request by showing example of your configuration, commands that you are running and old entries not removed?

Thanks

My network.interfaces.new (censored)

# network interface settings; autogenerated
# Please do NOT modify this file directly, unless you know what
# you're doing.
#
# If you want to manage parts of the network configuration manually,
# please utilize the 'source' or 'source-directory' directives to do
# so.
# PVE will preserve these directives, but will NOT read its network
# configuration from sourced files, so do not attempt to move any of
# the PVE managed interfaces into external files!

source /etc/network/interfaces.d/*

auto lo
iface lo inet loopback

iface lo inet6 loopback

auto enp4s0
iface enp4s0 inet static
    address 5.x.x.x/27
    gateway 5.x.x.x
    pointopoint 5.x.x.x
    up route add -net 5.x.x.x netmask 255.255.255.224 gw 5.x.x.x dev enp4s0
# route 5.x.x.x/27 via 5.x.x.x

iface enp4s0 inet6 static
    address 2a01:x:x:x::2/64
    gateway fe80::1

auto vmbr0
iface vmbr0 inet static
    address 5.x.x.x/27
    bridge-ports none
    bridge-stp off
    bridge-fd 0

iface vmbr0 inet6 static
    address 2a01:x:x:x::2/64

auto vmbr1
iface vmbr1 inet static
    address 192.168.0.254/24
    bridge-ports none
    bridge-stp off
    bridge-fd 0
    post-up echo 1 > /proc/sys/net/ipv4/ip_forward
    post-up iptables -t nat -A POSTROUTING -s '192.168.0.0/24' -o enp4s0 -j MASQUERADE
    post-down iptables -t nat -D POSTROUTING -s '192.168.0.0/24' -o enp4s0 -j MASQUERADE
    ############################
    # VM/Container 100 
    # Interne IP:192.168.0.100' 
    # 
    # Dienst: "Remote Desktop RDP" mit Port: 3389 erreichbar über 5.x.x.x:3389 
    post-up iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 3389 -j DNAT --to 192.168.0.100:3389 
    post-down iptables -t nat -D PREROUTING -i enp4s0 -p tcp --dport 3389 -j DNAT --to 192.168.0.100:3389 
    #
    # Dienst: "SFTP" mit Port: 22 erreichbar über 5.x.x.x:1021 
    post-up iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 1021 -j DNAT --to 192.168.0.100:21 
    post-down iptables -t nat -D PREROUTING -i enp4s0 -p tcp --dport 1021 -j DNAT --to 192.168.0.100:21
        ############################

For example i remove the last two entries (1021 -> 21), saving the file and append it via proxmox interface 7.3-3.

Then i run iptables-save > /etc/network/interfaces/rules.v4 and inspecting it.

# Generated by iptables-save v1.8.7 on Sun Dec  4 18:40:40 2022
*raw
:PREROUTING ACCEPT [1048991:297288166]
:OUTPUT ACCEPT [37100:13388446]
COMMIT
# Completed on Sun Dec  4 18:40:40 2022
# Generated by iptables-save v1.8.7 on Sun Dec  4 18:40:40 2022
*filter
:INPUT ACCEPT [740:305855]
:FORWARD ACCEPT [28143:11639838]
:OUTPUT ACCEPT [703:190298]
COMMIT
# Completed on Sun Dec  4 18:40:40 2022
# Generated by iptables-save v1.8.7 on Sun Dec  4 18:40:40 2022
*nat
:PREROUTING ACCEPT [8903:756608]
:INPUT ACCEPT [350:19235]
:OUTPUT ACCEPT [14:838]
:POSTROUTING ACCEPT [1000:53345]
-A PREROUTING -i enp4s0 -p tcp -m tcp --dport 3389 -j DNAT --to-destination 192.168.0.100:3389
-A PREROUTING -i enp4s0 -p tcp -m tcp --dport 1021 -j DNAT --to-destination 192.168.0.100:21
-A POSTROUTING -s 192.168.0.0/24 -o enp4s0 -j MASQUERADE
-A POSTROUTING -s 192.168.0.0/24 -o enp4s0 -j MASQUERADE
-A POSTROUTING -s 192.168.0.0/24 -o enp4s0 -j MASQUERADE

And seeing it is still in there. (Ignore the time stamp in this file, i know it is from sunday.)

[julienfortin]

Can you also post ifreload -ad logs? You should be able to see which commands were executed.

[dandud100]

ifreload -ad

ifreload -ad
debug: args = Namespace(all=True, currentlyup=False, CLASS=None, iflist=[], noact=False, verbose=False, debug=True, withdepends=False, perfmode=False, nocache=False, excludepats=None, usecurrentconfig=False, syslog=False, force=False, syntaxcheck=False, version=None, nldebug=False)
debug: creating ifupdown object ..
info: requesting link dump
info: requesting address dump
info: requesting netconf dump
debug: nlcache: reset errorq
debug: {'use_daemon': 'no', 'template_enable': '1', 'template_engine': 'mako', 'template_lookuppath': '/etc/network/ifupdown2/templates', 'default_interfaces_configfile': '/etc/network/interfaces', 'disable_cli_interfacesfile': '0', 'addon_syntax_check': '0', 'addon_scripts_support': '1', 'addon_python_modules_support': '1', 'multiple_vlan_aware_bridge_support': '1', 'ifquery_check_success_str': 'pass', 'ifquery_check_error_str': 'fail', 'ifquery_check_unknown_str': '', 'ifquery_ifacename_expand_range': '0', 'link_master_slave': '1', 'delay_admin_state_change': '0', 'ifreload_down_changed': '0', 'addr_config_squash': '0', 'ifaceobj_squash': '0', 'adjust_logical_dev_mtu': '1', 'state_dir': '/run/network/'}
info: loading builtin modules from ['/usr/share/ifupdown2/addons']
info: module openvswitch not loaded (module init failed: no /usr/bin/ovs-vsctl found)
info: module openvswitch_port not loaded (module init failed: no /usr/bin/ovs-vsctl found)
info: module ppp not loaded (module init failed: no /usr/bin/pon found)
info: module batman_adv not loaded (module init failed: no /usr/sbin/batctl found)
debug: bridge: using reserved vlan range (0, 0)
debug: bridge: init: warn_on_untagged_bridge_absence=False
debug: bridge: init: vxlan_bridge_default_igmp_snooping=None
debug: bridge: init: arp_nd_suppress_only_on_vxlan=False
debug: bridge: init: bridge_always_up_dummy_brport=None
info: executing /sbin/sysctl net.bridge.bridge-allow-multiple-vlans
debug: bridge: init: multiple vlans allowed True
info: module mstpctl not loaded (module init failed: no /sbin/mstpctl found)
info: executing /bin/ip rule show
info: executing /bin/ip -6 rule show
info: module ethtool not loaded (module init failed: /sbin/ethtool: not found)
info: address: using default mtu 1500
info: address: max_mtu undefined
info: executing /usr/sbin/ip vrf id
info: mgmt vrf_context = False
info: dhclient: dhclient_retry_on_failure set to 0
info: executing /bin/ip addr help
info: address metric support: OK
info: module ethtool not loaded (module init failed: /sbin/ethtool: not found)
info: module ppp not loaded (module init failed: no /usr/bin/pon found)
info: module mstpctl not loaded (module init failed: no /sbin/mstpctl found)
info: module batman_adv not loaded (module init failed: no /usr/sbin/batctl found)
info: module openvswitch_port not loaded (module init failed: no /usr/bin/ovs-vsctl found)
info: module openvswitch not loaded (module init failed: no /usr/bin/ovs-vsctl found)
info: looking for user scripts under /etc/network
info: loading scripts under /etc/network/if-pre-up.d ...
info: loading scripts under /etc/network/if-up.d ...
info: loading scripts under /etc/network/if-post-up.d ...
info: loading scripts under /etc/network/if-pre-down.d ...
info: loading scripts under /etc/network/if-down.d ...
info: loading scripts under /etc/network/if-post-down.d ...
info: 'link_master_slave' is set. slave admin state changes will be delayed till the masters admin state change.
info: using mgmt iface default prefix eth
debug: reloading interface config ..
info: processing interfaces file /etc/network/interfaces
debug: processing sourced line ..'source /etc/network/interfaces.d/*'
info: no interfaces to down ..
info: reload: scheduling up on interfaces: ['lo', 'enp4s0', 'vmbr0', 'vmbr1']
debug: scheduling '['pre-up', 'up', 'post-up']' for ['lo', 'enp4s0', 'vmbr0', 'vmbr1']
debug: dependency graph {
        lo : []
        enp4s0 : []
        vmbr0 : []
        vmbr1 : []
}
debug: graph roots (interfaces that dont have dependents): ['lo', 'enp4s0', 'vmbr0', 'vmbr1']
info: lo: running ops ...
debug: lo: pre-up : running module xfrm
debug: lo: pre-up : running module link
debug: lo: pre-up : running module bond
debug: lo: pre-up : running module vlan
debug: lo: pre-up : running module vxlan
debug: lo: pre-up : running module usercmds
debug: lo: pre-up : running module bridge
debug: lo: pre-up : running module bridgevlan
debug: lo: pre-up : running module tunnel
debug: lo: pre-up : running module vrf
debug: lo: pre-up : running module address
info: executing /sbin/sysctl net.mpls.conf.lo.input=0
debug: lo: up : running module dhcp
debug: lo: up : running module address
debug: lo: up : running module addressvirtual
debug: lo: up : running module usercmds
debug: lo: up : running script /etc/network/if-up.d/postfix
info: executing /etc/network/if-up.d/postfix
warning: lo: up cmd '/etc/network/if-up.d/postfix' failed ([Errno 13] Permission denied: '/etc/network/if-up.d/postfix')
debug: lo: post-up : running module usercmds
debug: lo: statemanager sync state pre-up
info: enp4s0: running ops ...
debug: enp4s0: pre-up : running module xfrm
debug: enp4s0: pre-up : running module link
debug: enp4s0: pre-up : running module bond
debug: enp4s0: pre-up : running module vlan
debug: enp4s0: pre-up : running module vxlan
debug: enp4s0: pre-up : running module usercmds
debug: enp4s0: pre-up : running module bridge
debug: enp4s0: pre-up : running module bridgevlan
debug: enp4s0: pre-up : running module tunnel
debug: enp4s0: pre-up : running module vrf
debug: enp4s0: pre-up : running module address
info: executing /sbin/sysctl net.mpls.conf.enp4s0.input=0
info: enp4s0: primary ip changed (from 5.x.x.x/27 to 5.x.x.65/32) we need to purge all ip addresses and re-add them
info: enp4s0: netlink: ip addr del 5.x.x.65/32 dev enp4s0
  File "/usr/sbin/ifreload", line 131, in <module>
    sys.exit(main())
  File "/usr/sbin/ifreload", line 119, in main
    return stand_alone()
  File "/usr/sbin/ifreload", line 103, in stand_alone
    status = ifupdown2.main()
  File "/usr/share/ifupdown2/ifupdown/main.py", line 77, in main
    self.handlers.get(self.op)(self.args)
  File "/usr/share/ifupdown2/ifupdown/main.py", line 284, in run_reload
    ifupdown_handle.reload(['pre-up', 'up', 'post-up'],
  File "/usr/share/ifupdown2/ifupdown/ifupdownmain.py", line 2437, in reload
    self._reload_default(*args, **kargs)
  File "/usr/share/ifupdown2/ifupdown/ifupdownmain.py", line 2415, in _reload_default
    ret = self._sched_ifaces(new_filtered_ifacenames, upops,
  File "/usr/share/ifupdown2/ifupdown/ifupdownmain.py", line 1558, in _sched_ifaces
    ifaceScheduler.sched_ifaces(self, ifacenames, ops,
  File "/usr/share/ifupdown2/ifupdown/scheduler.py", line 588, in sched_ifaces
    cls.run_iface_list(ifupdownobj, run_queue, ops,
  File "/usr/share/ifupdown2/ifupdown/scheduler.py", line 318, in run_iface_list
    cls.run_iface_graph(ifupdownobj, ifacename, ops, parent,
  File "/usr/share/ifupdown2/ifupdown/scheduler.py", line 308, in run_iface_graph
    cls.run_iface_list_ops(ifupdownobj, ifaceobjs, ops)
  File "/usr/share/ifupdown2/ifupdown/scheduler.py", line 181, in run_iface_list_ops
    cls.run_iface_op(ifupdownobj, ifaceobj, op,
  File "/usr/share/ifupdown2/ifupdown/scheduler.py", line 102, in run_iface_op
    m.run(ifaceobj, op,
  File "/usr/share/ifupdown2/addons/address.py", line 1401, in run
    op_handler(self, ifaceobj,
  File "/usr/share/ifupdown2/addons/address.py", line 1036, in _pre_up
    self.process_addresses(ifaceobj, ifaceobj_getfunc, force_reapply)
  File "/usr/share/ifupdown2/addons/address.py", line 605, in process_addresses
    self.log_warn(str(e))
  File "/usr/share/ifupdown2/ifupdownaddons/modulebase.py", line 97, in log_warn
    traceback.print_stack()
Traceback (most recent call last):
  File "/usr/share/ifupdown2/lib/nlcache.py", line 3214, in addr_del
    result = self.tx_nlpacket_get_response_with_error(packet)
  File "/usr/share/ifupdown2/lib/nlcache.py", line 2277, in tx_nlpacket_get_response_with_error
    raise Exception(error_str)
Exception: operation failed with 'Cannot assign requested address' (99)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/share/ifupdown2/addons/address.py", line 603, in process_addresses
    self.netlink.addr_del(ifname, addr)
  File "/usr/share/ifupdown2/lib/nlcache.py", line 3222, in addr_del
    raise NetlinkError(e, "cannot delete address %s dev %s" % (addr, ifname), ifname=ifname)
lib.nlcache.NetlinkError: netlink: enp4s0: cannot delete address 5.x.x.65/32 dev enp4s0: operation failed with 'Cannot assign requested address' (99)
warning: netlink: enp4s0: cannot delete address 5.x.x.65/32 dev enp4s0: operation failed with 'Cannot assign requested address' (99)
info: enp4s0: netlink: ip addr add 5.x.x.x/27 dev enp4s0 peer 5.x.x.65/32
debug: enp4s0: up : running module dhcp
debug: enp4s0: up : running module address
info: executing /bin/ip route add default via 5.x.x.65 proto kernel dev enp4s0 onlink
info: executing /bin/ip route add default via fe80::1 proto kernel dev enp4s0 onlink
debug: enp4s0: up : running module addressvirtual
debug: enp4s0: up : running module usercmds
info: executing route add -net 5.x.x.64 netmask 255.255.255.224 gw 5.x.x.65 dev enp4s0
debug: enp4s0: up : running script /etc/network/if-up.d/postfix
info: executing /etc/network/if-up.d/postfix
warning: enp4s0: up cmd '/etc/network/if-up.d/postfix' failed ([Errno 13] Permission denied: '/etc/network/if-up.d/postfix')
debug: enp4s0: post-up : running module usercmds
debug: enp4s0: statemanager sync state pre-up
info: vmbr0: running ops ...
debug: vmbr0: pre-up : running module xfrm
debug: vmbr0: pre-up : running module link
debug: vmbr0: pre-up : running module bond
debug: vmbr0: pre-up : running module vlan
debug: vmbr0: pre-up : running module vxlan
debug: vmbr0: pre-up : running module usercmds
debug: vmbr0: pre-up : running module bridge
info: vmbr0: bridge already exists
info: vmbr0: applying bridge settings
info: vmbr0: reset bridge-hashel to default: 4
info: vmbr0: reset bridge-hashmax to default: 512
info: reading '/sys/class/net/vmbr0/bridge/stp_state'
info: vmbr0: netlink: ip link set dev vmbr0 type bridge (with attributes)
debug: attributes: {26: 4, 27: 512}
debug: vmbr0: pre-up : running module bridgevlan
debug: vmbr0: pre-up : running module tunnel
debug: vmbr0: pre-up : running module vrf
debug: vmbr0: pre-up : running module address
info: executing /sbin/sysctl net.mpls.conf.vmbr0.input=0
info: writing '0' to file /proc/sys/net/ipv4/conf/vmbr0/arp_accept
debug: vmbr0: up : running module dhcp
debug: vmbr0: up : running module address
debug: vmbr0: up : running module addressvirtual
debug: vmbr0: up : running module usercmds
debug: vmbr0: up : running script /etc/network/if-up.d/postfix
info: executing /etc/network/if-up.d/postfix
warning: vmbr0: up cmd '/etc/network/if-up.d/postfix' failed ([Errno 13] Permission denied: '/etc/network/if-up.d/postfix')
debug: vmbr0: post-up : running module usercmds
debug: vmbr0: statemanager sync state pre-up
info: vmbr1: running ops ...
debug: vmbr1: pre-up : running module xfrm
debug: vmbr1: pre-up : running module link
debug: vmbr1: pre-up : running module bond
debug: vmbr1: pre-up : running module vlan
debug: vmbr1: pre-up : running module vxlan
debug: vmbr1: pre-up : running module usercmds
debug: vmbr1: pre-up : running module bridge
info: vmbr1: bridge already exists
info: vmbr1: applying bridge settings
info: vmbr1: reset bridge-hashel to default: 4
info: vmbr1: reset bridge-hashmax to default: 512
info: reading '/sys/class/net/vmbr1/bridge/stp_state'
info: vmbr1: netlink: ip link set dev vmbr1 type bridge (with attributes)
debug: attributes: {26: 4, 27: 512}
info: vmbr1: port tap100i0 will stay enslaved as it matches with bridge-ports-condone-regex
info: vmbr1: port veth102i0 will stay enslaved as it matches with bridge-ports-condone-regex
info: vmbr1: port tap104i0 will stay enslaved as it matches with bridge-ports-condone-regex
info: vmbr1: applying bridge configuration specific to ports
debug: vmbr1: cannot find bridgeports
debug: vmbr1: _get_bridge_mac returned (None, None)
info: executing /sbin/bridge fdb replace de:x:x:x:x:x dev vmbr1  self 
debug: vmbr1: pre-up : running module bridgevlan
debug: vmbr1: pre-up : running module tunnel
debug: vmbr1: pre-up : running module vrf
debug: vmbr1: pre-up : running module address
info: executing /sbin/sysctl net.mpls.conf.vmbr1.input=0
info: writing '0' to file /proc/sys/net/ipv4/conf/vmbr1/arp_accept
debug: vmbr1: up : running module dhcp
debug: vmbr1: up : running module address
debug: vmbr1: up : running module addressvirtual
debug: vmbr1: up : running module usercmds
debug: vmbr1: up : running script /etc/network/if-up.d/postfix
info: executing /etc/network/if-up.d/postfix
warning: vmbr1: up cmd '/etc/network/if-up.d/postfix' failed ([Errno 13] Permission denied: '/etc/network/if-up.d/postfix')
debug: vmbr1: post-up : running module usercmds
info: executing echo 1 > /proc/sys/net/ipv4/ip_forward
info: executing iptables -t nat -A POSTROUTING -s '192.168.0.0/24' -o enp4s0 -j MASQUERADE
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 3389 -j DNAT --to 192.168.0.100:3389
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 1021 -j DNAT --to 192.168.0.100:21
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 990 -j DNAT --to 192.168.0.100:990
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 989 -j DNAT --to 192.168.0.100:989
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 10987 -j DNAT --to 192.168.0.100:10987
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 10986 -j DNAT --to 192.168.0.100:10986
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 10985 -j DNAT --to 192.168.0.100:10985
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p udp --dport 27016 -j DNAT --to 192.168.0.100:27016
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p udp --dport 25565 -j DNAT --to 192.168.0.100:25565
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 25565 -j DNAT --to 192.168.0.100:25565
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p udp --dport 25566 -j DNAT --to 192.168.0.100:25566
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 25566 -j DNAT --to 192.168.0.100:25566
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 8124 -j DNAT --to 192.168.0.100:8124
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p udp --dport 7777 -j DNAT --to 192.168.0.100:7777
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 7777 -j DNAT --to 192.168.0.100:7777
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p udp --dport 27015 -j DNAT --to 192.168.0.100:27015
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p udp --dport 28015 -j DNAT --to 192.168.0.100:28015
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 1122 -j DNAT --to 192.168.0.101:22
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p udp --dport 9987 -j DNAT --to 192.168.0.102:9987
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 30033 -j DNAT --to 192.168.0.102:30033
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 10011 -j DNAT --to 192.168.0.102:10011
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p udp --dport 2010 -j DNAT --to 192.168.0.102:2010
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 41144 -j DNAT --to 192.168.0.102:41144
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 2008 -j DNAT --to 192.168.0.102:2008
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 1222 -j DNAT --to 192.168.0.102:22
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 8087 -j DNAT --to 192.168.0.102:8087
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 1322 -j DNAT --to 192.168.0.103:22
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 1422 -j DNAT --to 192.168.0.104:22
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 2022 -j DNAT --to 192.168.0.104:2022
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 80 -j DNAT --to 192.168.0.104:80
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 8080 -j DNAT --to 192.168.0.104:8080
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p tcp --dport 443 -j DNAT --to 192.168.0.104:443
info: executing iptables -t nat -A PREROUTING -i enp4s0 -p udp --dport 34197 -j DNAT --to 192.168.0.104:34197
debug: vmbr1: statemanager sync state pre-up
debug: saving state ..
info: exit status 0

[itkfm]

Seems like ifreload -a does not execute post-down commands

[PanForPancakes]

Can confirm, post-downs are not being executed, which is not intuitive. It would be really nice if ifreload did though

[hd-px]

Can also confirm, that the (pre/post-)down hooks are only executed if an interface gets removed, which is described in the documentation as well.

$ man ifreload Runs ifdown on interfaces that were removed from the file and subsequently runs ifup on all interfaces.

The Question is, does this behavior make sense ?

[julienfortin]

I don't have the bandwidth to look into this, but i agree with you guys, ifreload should also pre/post-down on removed interfaces.

[itkfm]

ifreload should also pre/post-down on removed interfaces.

It should also do so on non-removed ones, just like it executes pre/post-up on them.

[itkfm]

The Question is, does this behavior make sense ?

Does it make sense? Technically, yes. Is it useful? Practically, no.