This doesn't seem to be much of a problem with prefixes less than or equal to /24. Domestically, Verio is the big exception. They seem to filter anything longer than a /20. -Ejay -----Original Message----- From: Temkin, David [mailto:temkin@sig.com] Sent: Wednesday, June 11, 2003 2:04 PM To: nanog@merit.edu Subject: Minimum prefix length? A few years ago I had an issue with a few of the larger carriers rejecting my routes (from a natural Class B space) because their prefix length was too short (at one point I simply had the /16 divided into two /17's and this still got rejected in some places). I can't remember which carriers exactly, but it may have been some larger transit providers like AboveNet/etc. Anyone know what the current attitude is by carriers about this? Nowadays with ever-growing memory and CPU it doesn't seem like it's as much of an issue. In an environment where we're all trying to conserve address space watching natural boundries doesn't seem all that smart. IMPORTANT:The information contained in this email and/or its attachments is confidential. If you are not the intended recipient, please notify the sender immediately by reply and immediately delete this message and all its attachments. Any review, use, reproduction, disclosure or dissemination of this message or any attachment by an unintended recipient is strictly prohibited. Neither this message nor any attachment is intended as or should be construed as an offer, solicitation or recommendation to buy or sell any security or other financial instrument. Neither the sender, his or her employer nor any of their respective affiliates makes any warranties as to the completeness or accuracy of any of the information contained herein or that this message or any of its attachments is free of viruses.