Eir’s email customers have been experiencing problems accessing their mail following a suspected Distributed Denial of Service (DDOS) attack by hackers.

Ireland’s biggest telco has an estimated 400,000 email users, with @eircom.net addresses. The firm noticed an issue last Wednesday and began its mitigation process. A DDOS attack is a malicious attempt to make a server or a network resource unavailable to users, usually by temporarily interrupting or suspending the services of a host connected to the internet.

An Eir spokesman said the vast majority of customers should be able to access their emails accounts again. He said the firm had received no contact with any hackers or any ransom demand.

Some users may still be encountering issues as the mitigation process sifts through IP addresses to sort out which are genuine and which may be part of an attack.