pmcmicha
Technical User
- May 25, 2000
- 353
The location in question has a cable connection for their internet that serves a business and other users. The cable modem is connected to a RVS4000 Cisco Small Business Router. The router has been configured to separate the users from the business using VLANs. Everything on the user side checks out and all but one item on the business side checks out.
The VLAN for the users is setup to act as a DHCP server, and has specified DNS servers.
The VLAN for the business side is not acting as DHCP server, and pulls DNS server information from the cable connection. The DHCP server for the business also acts as a DNS server for everything going through it. The reservation software for the business has been in place for a few months without many problems. The issue started yesterday and continues today. It will go up and down on its connection status. The reservation software requires that four ports be open and accessible at all times, these ports continue to remain open. According to the reservation software support, there is a "Route Flapping" issue occurring, which is why the connection keeps going up and down, even though all other websites and destinations on the internet are accessible.
In addition to the business defined DNS server, the backup DNS entries are for 8.8.8.8 and 8.8.4.4.
After some analysis with nslookup, I found that the business and Google DNS servers all come up with the same IP address for the primary website that the reservation software connects to retrieve information. However, when I use nslookup with the cable provided DNS server, it comes back with a 172.233.xxx.xxx address instead of the 66.151.xxx.xxx address.
My question is, could this be the "Route Flapping" issue that the support technician says exists even though we are not specifically using the cable provided DNS servers?
Thanks in advance for any help that can be provided.
The VLAN for the users is setup to act as a DHCP server, and has specified DNS servers.
The VLAN for the business side is not acting as DHCP server, and pulls DNS server information from the cable connection. The DHCP server for the business also acts as a DNS server for everything going through it. The reservation software for the business has been in place for a few months without many problems. The issue started yesterday and continues today. It will go up and down on its connection status. The reservation software requires that four ports be open and accessible at all times, these ports continue to remain open. According to the reservation software support, there is a "Route Flapping" issue occurring, which is why the connection keeps going up and down, even though all other websites and destinations on the internet are accessible.
In addition to the business defined DNS server, the backup DNS entries are for 8.8.8.8 and 8.8.4.4.
After some analysis with nslookup, I found that the business and Google DNS servers all come up with the same IP address for the primary website that the reservation software connects to retrieve information. However, when I use nslookup with the cable provided DNS server, it comes back with a 172.233.xxx.xxx address instead of the 66.151.xxx.xxx address.
My question is, could this be the "Route Flapping" issue that the support technician says exists even though we are not specifically using the cable provided DNS servers?
Thanks in advance for any help that can be provided.