Sign up ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

I really need to know this for a linux server, but since it also applies to client OSes, I figured the question should be posed here instead of server fault.

share|improve this question

3 Answers 3

up vote 13 down vote accepted

According to the replies to this post to the linux-net mailing list,

  • At one point, the Linux kernel had a limit of 255 aliases per physical interface device.
  • As of Linux kernel version 2.2, there is no (practical) limit, with the second response citing personal experience with having aliased over 5,000 addresses to a single ethernet card.

Of course, binding large numbers of aliases to a single device will impose memory requirements and may have performance implications, so it's entirely possible that your hardware may limit the number of aliases you can add, even if the kernel itself doesn't.

share|improve this answer
There's no need to create aliases for this; ip addr add can bind the addresses to a single device. – Ignacio Vazquez-Abrams Jan 11 '11 at 10:03
Yes, and it does so by aliasing additional addresses onto the same device. Whether the alias is named (eth0:0) or not, it's still an alias. Granted, the authors of the ip(8) man page choose not to use the term "alias" because it treats all addresses as equal, pretty much the entire rest of the world agrees that assigning multiple addresses to the same interface is called "IP aliasing". – Dave Sherohman Jan 11 '11 at 15:32

More than you could ever possibly need. Use ip addr add to add addresses to an interface.

share|improve this answer

The maximum would be 4,294,967,294 IP addresses (assuming you're talking about IPV4, you have enough RAM, and we take out one for the broadcast address and one for the network address).

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.