0 Replies Latest reply: Jan 15, 2014 12:11 PM by cmsdloma RSS

    Slingbox PRO-HD always wants to contact 4.2.2.1 for DNS

    cmsdloma Newbie

      I have discovered that the Slingbox PRO-HD tries to directly contact 4.2.2.1 for DNS, even though the DHCP server tells it to use the local router (192.168.42.254) which runs a DNS caching server.  I found this in my IPTables firewall logs:

       

      an 15 19:45:53 Artigo kernel: [62108.535922] IPT: Rejected DNS Forw: IN=br0 OUT=tun0 PHYSIN=eth0 SRC=192.168.42.91 DST=4.2.2.1 LEN=62 TOS=0x00 PREC=0x00 TTL=63 ID=3108 PROTO=UDP SPT=28521 DPT=53 LEN=42
      Jan 15 19:45:54 Artigo kernel: [62109.540149] IPT: Rejected DNS Forw: IN=br0 OUT=tun0 PHYSIN=eth0 SRC=192.168.42.91 DST=4.2.2.1 LEN=62 TOS=0x00 PREC=0x00 TTL=63 ID=3109 PROTO=UDP SPT=28521 DPT=53 LEN=42
      Jan 15 19:45:55 Artigo kernel: [62110.535806] IPT: Rejected DNS Forw: IN=br0 OUT=tun0 PHYSIN=eth0 SRC=192.168.42.91 DST=4.2.2.1 LEN=62 TOS=0x00 PREC=0x00 TTL=63 ID=3110 PROTO=UDP SPT=28521 DPT=53 LEN=42
      Jan 15 19:45:56 Artigo kernel: [62111.550146] IPT: Rejected DNS Forw: IN=br0 OUT=tun0 PHYSIN=eth0 SRC=192.168.42.91 DST=4.2.2.1 LEN=62 TOS=0x00 PREC=0x00 TTL=63 ID=3111 PROTO=UDP SPT=28521 DPT=53 LEN=42
      Jan 15 19:45:57 Artigo kernel: [62112.545848] IPT: Rejected DNS Forw: IN=br0 OUT=tun0 PHYSIN=eth0 SRC=192.168.42.91 DST=4.2.2.1 LEN=62 TOS=0x00 PREC=0x00 TTL=63 ID=3112 PROTO=UDP SPT=28521 DPT=53 LEN=42

       

      FYI: Artigo is the name of my router, 192.168.42.91 is the Slingbox (reserved by DHCP).  For anyone who doens't know, 4.2.2.1 is one of the root name servers on the Internet.

       

      Network communication to/from the Slingbox is OK, and it slings happily across the Internet.  It also gets an IP address correctly from the DHCP server.  Everything is still working perfectly.

       

      But my question is, why does it ignore the DHCP server's suggested DNS, and always try to contact 4.2.2.1 as a DNS server directly?  Is this behavior correct?  I don't like it!

       

      I came across this because I am doing parental control at the DNS level on my router, and I blocked other DNS servers, so that all DNS requests must go through my router.

       

      Anyone any ideas?  Ta.

       

      Dave