Thunderbird doesn’t find servers under WiFi.

A weird thing happened. My thunderbird, a popular open source email client did not work at home unlike my office. It said that it could not find servers for imap. Actually, I perceived the issue a long time ago, but thought it was just a temporary glitch from an internet service provider. However, it was naive thought. Yesterday I had to work on something on my linux laptop. Opened the laptop, clicked the thunderbird. No… The bug I saw last month was still existing there. So I decided to look into the under the hood and finally got why.

In a nutshell, It is hard to blame a specific one for the issue. Where a router does not have DNS info and your thunderbird enabled IPv6 is connected to internet via the router, the problem happens. For detouring the issue, you can choose either two options to get your thunderbird work.

  1. Disable the IPv6 option in thunderbird. 
    The relevant option placed at Edit > Preferences > Advanced > Config Editor… And then put “IPv6” in the search bar. You can find network.dns.disableIPv6. Its default value is false. Double click to make it true.
  2. You can explicitly set domain servers compatible for IPv6 to your router. 
    My router is TP-LINK’s TL-WDR3600, it seems not working well with IPv6 if domain name servers are not specified. They are optional so left empty as default. Go to router’s config page and put your DNSs in the DHCP tab. In my case, I just used google’s public domain name servers. i.e. as a primary DNS and as a secondary DNS.

I hope this note to help somebody facing a same issue like mine.