A Californian ISP managed to screw up the routing for IOL, Indigo and other Irish internet users. On Saturday 07 November, it started to advertise a route 194.125.0.0/20 This meant that packets for addresses between 194.125.0.0 to 194.125.15.255 went to California. The problem was compounded by a system wide outage on IOL's upstream supplier, UUNET between 1800 and 2200 Hrs on Sunday 8 November.

IOL rapidly traced the routing problem and contacted the ISP in question and on Sunday morning the ISP stopped advertising the faulty routing information. Things are coming back to normal though the aftershocks are still being felt.

Since late Saturday afternoon, internet access in Ireland had been erratic. IOL was upgrading their transatlantic link to double the existing bandwidth. However the screw up by a Californian ISP meant that direct access to US sites was not possible for most IOL users over the weekend. However when the proxy was set to cache.iol.ie it seemed to work. A posting from Barry Flanagan to the iol.announce newsgroup stated that IOL was working to fix the problem as quickly as possible.

Outages were not confined to IOL users. Tinet and Indigo lost access to IOL at various stages as the faulty routing tables started to take effect. When tracerouting the Tinet and Indigo connections, it seemed that everything stopped at the INEX, (the Irish internet exchange which routes packets for Irish ISPs locally). A check with a leased line user on TInet's system last night around 2245 Hrs indicated that any packets for IOL were being routed via Amsterdam and out to the US. The INEX connections for Esat and HEAnet seemed fine. With IOL still trying to route packets to the Tinet/Indigo INEX connections and Tinet routing packets to IOL's US connection, it seems that there was a bit of a communications breakdown in progress.

The situation is returning to normal with IOL, Indigo and Tinet all visible to each other again. IOL's US bandwidth does indeed seem to be better and US sites are loading faster.