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Wifi status is connected but not able to connect to MQTT

I am using esp32 and I am able to connect to wifi successfully but it seems it's not able to talk to MQTT client or any other service.
mos console keeps on showing "Failed to resolve time.google.com, server 202.56.215.250"

Comments

  • Nothing to do with Mongoose OS.

    Failed to resolve time.google.com, server 202.56.215.250 = DNS issue. 202.56.215.250 doesn't look like a DNS server.

  • @nliviu I am able to connect my mobile to the same wifi and browse but not with ESP32. Do you think of any unique problem which can happen only to ESP32?

  • From my location your DNS server 202.56.215.250 is not responding:

    dig @202.56.215.250 google.com
    ; <<>> DiG 9.10.6 <<>> @202.56.215.250 google.com
    ; (1 server found)
    ;; global options: +cmd
    ;; connection timed out; no servers could be reached
    
    dig @202.56.215.250 time.google.com
    ; <<>> DiG 9.10.6 <<>> @202.56.215.250 time.google.com
    ; (1 server found)
    ;; global options: +cmd
    ;; connection timed out; no servers could be reached
    

    Can you ping time.google.com on a computer using the same DNS server?

  • @nliviu Thank you. It happened at a client location where we installed our device. I will try this next time I go there to debug

  • @nliviu I am able to ping time.google.com from my laptop which is connected to the same internet but I noticed ping response is coming from time2.google.com, 64 bytes from time2.google.com (216.239.35.4) .

  • time.google.com is a pool of several servers.
    Are you sure you use the same DNS server?

  • @nliviu I am so sorry. I am not an expert in networking. I am not able to understand "Are you sure you use the same DNS server?" this question. My esp32 and laptop are connected to the same wi-fi network. Can you please simplify the question if it is possible?

  • nliviunliviu Romania
    edited November 21

    Supposing you are on Windows, ipconfig /all will show the DNS servers:

    zzz adapter:
       Physical Address. . . . . . . . . : xx-xx-xx-xx-xx-xx
       DHCP Enabled. . . . . . . . . . . : No
       Autoconfiguration Enabled . . . . : Yes
       IPv4 Address. . . . . . . . . . . : aaa.bbb.bbb.ddd
       Subnet Mask . . . . . . . . . . . : eee.fff.ggg.ggg
       Default Gateway . . . . . . . . . : hhh.iii.jjj.kkk
       DNS Servers . . . . . . . . . . . : lll.mmm.nnn.ooo
    

    Or nslookup time.google.com

    Server:  dns-server-name
    Address:  dns-server-IP
    
    Non-authoritative answer:
    Name:    time.google.com
    Addresses:  2001:4860:4806:8::
              2001:4860:4806:c::
              2001:4860:4806:4::
              2001:4860:4806::
              216.239.35.8
              216.239.35.4
              216.239.35.0
              216.239.35.12
    
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