TRY THIS Rpi 2020.3 add-fqdn returns IPv6 address on IPv4 ADSL

[ostridge]

# add-fqdn at Line 20
# iptest=`nslookup $2 | tail -2 | cut -f 2 -d " " | head -n 1`

root@incrediblepbx:~# nslookup pbxinaflash.com | tail -2 | cut -f 2 -d " " | head -n 1
2606:4700:20::681a:5b8
root@incrediblepbx:~#

_____________________________________________________

#add-fqdn at line 19 (Raspi13-12)
#iptest=`nslookup $2 | tail -2 | cut -f 2 -d " " | head -n 1`


root@raspi-13:~# nslookup pbxinaflash.com | tail -2 | cut -f 2 -d " " | head -n 1
104.26.5.184
root@incrediblepbx:~#
root@raspi-13:~# nslookup sipgate.co.uk | tail -2 | cut -f 2 -d " " | head -n 1
217.10.79.23
root@raspi-13:~#

 

[wardmundy]

@ostridge: https://www.leowkahman.com/2016/03/19/disable-ipv6-raspberry-raspbian/

 

[jerrm]

@ostridge: https://www.leowkahman.com/2016/03/19/disable-ipv6-raspberry-raspbian/

Disabling IPv6 won't prevent nslookup from returning an IPv6 address if the upstream server sends it. Set -type=A on the command line or grep it away.

From a buster host:

IPv6 is disabled (and was at boot)

root@pi4dev:~# sysctl net.ipv6.conf.all.disable_ipv6 net.ipv6.conf.default.disable_ipv6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1

nslookup version:

root@pi4dev:~# nslookup -version
nslookup 9.11.5-P4-5.1-Raspbian

Lookup addresses:

root@pi4dev:~# nslookup www.google.com 1.1.1.1
Server:         1.1.1.1
Address:        1.1.1.1#53

Non-authoritative answer:
Name:   www.google.com
Address: 172.217.164.36
Name:   www.google.com
Address: 2607:f8b0:4002:c08::67


root@pi4dev:~# nslookup -type=A www.google.com 1.1.1.1
Server:         1.1.1.1
Address:        1.1.1.1#53

Non-authoritative answer:
Name:   www.google.com
Address: 172.217.164.36

 

[ostridge]

@ostridge: https://www.leowkahman.com/2016/03/19/disable-ipv6-raspberry-raspbian/

 

[ostridge]

IPv6 is disabled (and was at boot)

Any idea how it was disabled. There was nothing in /etc/sysctl.conf ?

 

[jerrm]

Any idea how it was disabled. There was nothing in /etc/sysctl.conf ?

I didn't mean to imply it is disabled by default on @wardmundy's image. Just showing that nslookup can return v6 addresses even if ipv6 is disabled.

FWIW, i always disable ipv6 (unless it's needed for some reason).

 

[ostridge]

Lookup addresses:

root@incrediblepbx:~#  nslookup  sipgate.co.uk
Server:         51.254.25.115
Address:        51.254.25.115#53

Non-authoritative answer:
Name:   sipgate.co.uk
Address: 217.10.79.23
Name:   sipgate.co.uk
Address: 2001:ab7::7
Name:   sipgate.co.uk
Address: 2001:ab7::6
Name:   sipgate.co.uk
Address: 2001:ab7::8
Name:   sipgate.co.uk
Address: 2001:ab7::5

root@incrediblepbx:~# nslookup -type=AAAA sipgate.co.uk |grep ddress:  | tail -2 | cut -f 2 -d " " | head -n 1
2001:ab7::5

root@incrediblepbx:~# nslookup -type=A sipgate.co.uk |grep ddress:  |tail -2| cut -f 2 -d " " | head -n 1
Address:        51.254.25.115#53 # no this is the dns server

root@incrediblepbx:~# nslookup -type=A sipgate.co.uk |grep ddress:  |tail -1| cut -f 2 -d " " | head -n 1
217.10.79.23
root@incrediblepbx:~#
root@incrediblepbx:~# nslookup -type=A sipgate.co.uk |tail -2| cut -f 2 -d " " | head -n 1
217.10.79.23
nslookup -type=A sipgate.co.uk |grep ddress:|tail -1| cut -f 2 -d " " | head -n 1
217.10.79.23

For the record this is the edit from line 19 of add-fqdn found in ipbx13-12

root@raspi-13:~# nslookup sipgate.co.uk | tail -2 | cut -f 2 -d " " | head -n 1
217.10.79.23

I'm thinking or maybe wishing - that maybe the script could harvest and whitelist the Ip4 and IP6 addresses where there are several?

 

[ostridge]

Just showing that nslookup can return v6 addresses even if ipv6 is disabled.

correct

 

[wardmundy]

Update has been pushed out. Thanks, @jerrm.

 

[ostridge]

The update worked OK thanks; but there is a harmless and minor inaccuracy - the text showing in ssh session upon the update is
"Checking for update20209. INSTALLED: TM3 add-fqdn update for IPv6 use"

I'm thinking that it isnt really for IP6 use rather to return IP4 address.