4 ms·

I'm a bit confused about the 'open resolvers' bit. I searched for the static IP range assigned by my ISP, and a number of results came up: http://openresolverp

I'm a bit confused about the 'open resolvers' bit. I searched for the static IP range assigned by my ISP, and a number of results came up: http://openresolverproject.org/search.cgi?mode=search4&search_for=109.224.131.0%2F24 http://openresolverproject.org/search.cgi?mode=search4&s... This range has a description of "Static IP Pool for xDSL End Users", so is it also home users who have open resolvers?

bluedino 14y ago
Very possible that the router provided by the ISP is mis-configured.
nwh 14y ago
Yep, my ISP has three open resolvers in my assigned range, and another 6 in the alternate range. It it grounds to give them a slight prod?
- noselasd 14y ago
  Your ISP doesn't have 3 open resolvers. Your neighbors have. Your ISP could terminate the contract with those 3 customers, but they won't - they're customers. They could block inbound trafic on port 25 to those 3 customers (if they knew about it), but they have no incentive to. Or they could block all inbound traffic on port 25, which will likely break DNS for a lot of customers.
  - baq 14y ago
    you meant port 53, i presume?
    - noselasd 14y ago
      ups. ofcourse.
    - nadinengland 14y ago
      I don't believe he/she did as for my ISP blocked port 80 and 443 making me resort to port 25 to send emails~
  - deleted 14y ago
    [deleted]
  - nwh 14y ago
    I meant that they exist within the ISPs ranges, not that the ISP itself owns them.
dmourati 14y ago
I was confused too. It seems the openresolverproject link is reporting more than just open resolvers. Those are active nameservers. I checked two nameserves I had set up at my previous dayjob and was surprised they were on the list. I then checked them manually with dig and found they were in fact not open. Confirmed with this tool: http://dns.measurement-factory.com/cgi-bin/openresolvercheck.pl http://dns.measurement-factory.com/cgi-bin/openresolvercheck... I think the RCODE is important. I also checked 8.8.8.8 but got a result I wasn't expecting.

bluedino 14y ago

Very possible that the router provided by the ISP is mis-configured.

nwh 14y ago

Yep, my ISP has three open resolvers in my assigned range, and another 6 in the alternate range. It it grounds to give them a slight prod?

noselasd 14y ago
Your ISP doesn't have 3 open resolvers. Your neighbors have. Your ISP could terminate the contract with those 3 customers, but they won't - they're customers. They could block inbound trafic on port 25 to those 3 customers (if they knew about it), but they have no incentive to. Or they could block all inbound traffic on port 25, which will likely break DNS for a lot of customers.
- baq 14y ago
  you meant port 53, i presume?
  - noselasd 14y ago
    ups. ofcourse.
  - nadinengland 14y ago
    I don't believe he/she did as for my ISP blocked port 80 and 443 making me resort to port 25 to send emails~
- deleted 14y ago
  [deleted]
- nwh 14y ago
  I meant that they exist within the ISPs ranges, not that the ISP itself owns them.

dmourati 14y ago

I was confused too. It seems the openresolverproject link is reporting more than just open resolvers. Those are active nameservers. I checked two nameserves I had set up at my previous dayjob and was surprised they were on the list. I then checked them manually with dig and found they were in fact not open. Confirmed with this tool: http://dns.measurement-factory.com/cgi-bin/openresolvercheck.pl http://dns.measurement-factory.com/cgi-bin/openresolvercheck... I think the RCODE is important. I also checked 8.8.8.8 but got a result I wasn't expecting.