Road Runner Problems
Checking for a Valid IP Address
NY Road Runner
Road Runner (RR) is a prominent ISP to many of the Rensselaer community. Recently, RR has upgraded its hardware. Due to these upgrades, RR service has been interrupted. Most noticeably, RR mail service will not work with mail.rpi.edu. Here are reasons why the RR service is not working. Please note, users of RR should contact them directly, as Rensselaer is not responsible for RR-related problems.
Some recent change made in the Timewarner/RoadRunner service has broken the reverse DNS lookup function for RoadRunner users. The practical effect on our user community is that RoadRunner users cannot retrieve mail from the campus mail server, mail.rpi.edu, which requires a successful reverse DNS lookup. Reverse DNS lookups are an important component of our anti-spam implementation, and we do not plan to relax the reverse DNS lookup requirements as a fix for the new problems with RoadRunner. Other (but not all) services and service providers on the Internet also require DNS lookups.
The problem is: RoadRunner HAS NOT kept its DNS servers up to date with all the new IP addresses it has added. Many of the newer IP addresses do not reverse map back to a valid domain name. The RPI mail server refuses connections from any system that does not have a valid reverse map....
This means you cannot read email from RPI (or use various other utilities that require reverse DNS lookups) via RoadRunner. This seems to be associated with the new cable modems. There were about 13,000 refused connections in the new address range on March 16, 1999.
Just so we don't cause a larger conflict with Road Runner by sending any users back to them in error, do one verifcation before you tell them it's RR's fault.
Ask them for their IP, which you can get through 'winipcfg'. Then, you should take their IP (x.x.x.x) and perform an nslookup on it:
A successful look up will look like:
~/ nslookup 188.8.131.52 Server: netserv6.its.rpi.edu Address: 184.108.40.206 Name: tejanb-2.stu.rpi.edu Address: 220.127.116.11An unsuccessful lookup will look like:
~/ nslookup 18.104.22.168 Server: netserv6.its.rpi.edu Address: 22.214.171.124 *** netserv6.its.rpi.edu can't find 126.96.36.199:Non-existent host/domainThis means it is very likely to be the Road Runner assigning bad IP problem. Be calm and level when dealing with these users. They've probably been given the run around by RR, and now you're telling them to go back and get run around some more.
We do have people working with Road Runner to resolve these problems, but it is their resposibility to service their customers. RR customers should look to RR tech support for further help or information. We can help them by informing them as to whether their IP is valid.