Experimental Physics and
Industrial Control System

So I just hardcoded in addr/bcast to see if the rest of the script would function correctly and now it gets down to the iptables command that sets up the rules.  But when I check sudo iptables -L -v -n I am not seeing it added for some reason.

 

jetson@ubuntu:/etc/network/if-up.d$ sudo ifup ens33

Internet Systems Consortium DHCP Client 4.3.5

Copyright 2004-2016 Internet Systems Consortium.

All rights reserved.

For info, please visit https://www.isc.org/software/dhcp/

 

Listening on LPF/ens33/00:0c:29:c6:6f:a0

Sending on   LPF/ens33/00:0c:29:c6:6f:a0

Sending on   Socket/fallback

DHCPDISCOVER on ens33 to 255.255.255.255 port 67 interval 3 (xid=0xe228736a)

DHCPREQUEST of 192.168.252.132 on ens33 to 255.255.255.255 port 67 (xid=0x6a7328e2)

DHCPOFFER of 192.168.252.132 from 192.168.252.254

DHCPACK of 192.168.252.132 from 192.168.252.254

cmp: EOF on /tmp/tmp.nKI1m7I1fj which is empty

/sbin/dhclient-script: 8: /etc/dhcp/dhclient-exit-hooks.d/chrony: /usr/lib/chrony/chrony-helper: not found

bound to 192.168.252.132 -- renewal in 889 seconds.

+ PORT=5064

+ [ dhcp != none ]

+ [ ens33 != lo ]

+ ip addr show ens33

+ line=2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000

    link/ether 00:0c:29:c6:6f:a0 brd ff:ff:ff:ff:ff:ff

    inet 192.168.252.132/24 brd 192.168.252.255 scope global ens33

       valid_lft forever preferred_lft forever

    inet6 fe80::20c:29ff:fec6:6fa0/64 scope link tentative

       valid_lft forever preferred_lft forever

+ addr=192.168.252.132

+ bcast=192.168.252.255

+ [ -z 192.168.252.132 -o -z 192.168.252.255 ]

+ [ start = start ]

+ iptables -t nat -A PREROUTING -d 192.168.252.132 -p udp --dport 5064 -j DNAT --to-destination 192.168.252.255

+ exit 0

 

jetson@ubuntu:/etc/network/if-up.d$ sudo iptables -L -v -n

Chain INPUT (policy ACCEPT 381K packets, 587M bytes)

pkts bytes target     prot opt in     out     source               destination        

 

Chain FORWARD (policy DROP 0 packets, 0 bytes)

pkts bytes target     prot opt in     out     source               destination        

    0     0 DOCKER-USER  all  --  *      *       0.0.0.0/0            0.0.0.0/0          

    0     0 DOCKER-ISOLATION-STAGE-1  all  --  *      *       0.0.0.0/0            0.0.0.0/0          

    0     0 ACCEPT     all  --  *      docker0  0.0.0.0/0            0.0.0.0/0            ctstate RELATED,ESTABLISHED

    0     0 DOCKER     all  --  *      docker0  0.0.0.0/0            0.0.0.0/0          

    0     0 ACCEPT     all  --  docker0 !docker0  0.0.0.0/0            0.0.0.0/0          

    0     0 ACCEPT     all  --  docker0 docker0  0.0.0.0/0            0.0.0.0/0          

 

Chain OUTPUT (policy ACCEPT 192K packets, 17M bytes)

pkts bytes target     prot opt in     out     source               destination        

 

Chain DOCKER (1 references)

pkts bytes target     prot opt in     out     source               destination        

 

Chain DOCKER-ISOLATION-STAGE-1 (1 references)

pkts bytes target     prot opt in     out     source               destination        

    0     0 DOCKER-ISOLATION-STAGE-2  all  --  docker0 !docker0  0.0.0.0/0            0.0.0.0/0          

    0     0 RETURN     all  --  *      *       0.0.0.0/0            0.0.0.0/0          

 

Chain DOCKER-ISOLATION-STAGE-2 (1 references)

pkts bytes target     prot opt in     out     source               destination        

    0     0 DROP       all  --  *      docker0  0.0.0.0/0            0.0.0.0/0          

    0     0 RETURN     all  --  *      *       0.0.0.0/0            0.0.0.0/0          

 

Chain DOCKER-USER (1 references)

pkts bytes target     prot opt in     out     source               destination        

    0     0 RETURN     all  --  *      *       0.0.0.0/0            0.0.0.0/0        

 

 

 

 

 

Thanks Heinz,

 

I seem to be still getting the return error from Ralph’s script even with the changes below that you mentioned. I did have to add the closing quotations on the last grep commands for addr/bcast, I was getting unterminated string error.

 

line=`ip addr show $IFACE`

addr=`echo $line | grep -Po 'inet\s+[^\s]+\s+' | grep -Po '\d+.*’ '`
bcast=`echo $line | grep -Po 'brd\s+[^\s]+\s+' | grep -Po '\d+.*’ '`

[ -z "$addr" -o -z "$bcast" ] && return 1

 

@Ralph

 

Here is what the script is going through, seems like the grep is still failing