CLAT/464XLAT not working in 19.07.1

For Developers
1

I was using CLAT in an Archer C7 v5 for some testing. Everything worked fine.

I decided then to upgrade to 19.07.1 and everything works fine from the backup that I did from the config, but not the CLAT (464XLAT).

I decided to reflash the unit from scratch and configure everything manually. Same problem, CLAT is not working. I tried even setting the tunnel link to the WAN interface manually in the CLAT interface (advanced settings), instead of the default "unspecified", played with the firewall settings as well, etc. Nothing resulted.

By the way, even in 18.06.7, which I'm using right now with the CLAT, the CLAT interface doesn't report any RX/TX or packets. In the same router I've installed Collectd and I can see there the traffic being graphed correctly.

So I'm guessing there is some bug there. I'm going to report it as a bug, but just in case someone discovered an easy solution.

2

The auto detection of the NAT64 Prefix doesn't seem to be working even on 22.03. But if I manually set the prefix to 64:ff9b::/96 which is the common prefix used by most providers, it starts working.

3

Worked fine for me, see Unable to get Quectel EC25-E to connect in QMI mode - #21 by AndrewZ

Do you have any response to nslookup ipv4only.arpa. ?

4

In my case, I use an external 5G CPE and connect to the OpenWRT device over ethernet to the WAN port of the OpenWRT device. Not sure if that changes things.

This is my config.

config interface 'wan'
        option device 'wan'
        option reqaddress 'try'
        option reqprefix 'auto'
        option proto 'dhcpv6'
        option iface_464xlat '0'
        option extendprefix '1'

config interface 'wan6_4'
        option proto '464xlat'
        option tunlink 'wan'
        option ip6prefix '64:ff9b::/96'

This is the output of nslookup ipv4only.arpa.

Server:         127.0.0.1
Address:        127.0.0.1:53

Non-authoritative answer:
Name:   ipv4only.arpa
Address: 192.0.0.170
Name:   ipv4only.arpa
Address: 192.0.0.171
1 Like
5

According to RFC7050:

A node requiring information about the presence (or absence) of
NAT64, and one or more Pref64::/n used for protocol translation SHALL
send a DNS query for AAAA resource records of the Well-Known
IPv4-only Name (WKN) "ipv4only.arpa.".

This is what I had during my test:

root@MF286D:~# nslookup ipv4only.arpa.
Server:         127.0.0.1
Address:        127.0.0.1:53

Non-authoritative answer:
Name:   ipv4only.arpa
Address: 192.0.0.171
Name:   ipv4only.arpa
Address: 192.0.0.170

Non-authoritative answer:
Name:   ipv4only.arpa
Address: 64:ff9b::c000:aa
Name:   ipv4only.arpa
Address: 64:ff9b::c000:ab

In your case it was no such answer from DNS so you had to configure Pref64 manually.

1 Like
6

i use 5G CPE and try to setup 464XLAT on TP-link MR200 since 4 day continues. but can't success :pensive:
so, i need your help regarding this. please :pray: help me.
i am waiting for your message...

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