topic Re: PA-820: Cable Type/Lengths and HA Port Questions in General Topics

PA-820: Cable Type/Lengths and HA Port Questions

J.Logan — Thu, 09 Oct 2025 15:01:58 GMT

I'm reorganizing the network racks at my workplace and am ordering new cabling.. A college of mine mentioned hearing something in the past that there may be an issue with using ethernet cables shorter than 3ft in some cases. I searched around but am having trouble finding concrete information outside of that it may have been an issue with older technology but potentially not newer, less to do with the cable type and more to do with the cable length specifically.

I'm planning on using Cat 6 UTP 6" cables for my two dedicated HA ports, a 6" cable for one interface port that is setup as HA backup and 2ft cables for interface and management ports to my Meraki MS150-48FP-4X, are those lengths sufficient or too short?
Do I need a crossover cable for my dedicated HA ports?

Re: PA-820: Cable Type/Lengths and HA Port Questions

JayGolf — Fri, 10 Oct 2025 03:49:25 GMT

Hi @J.Logan ,

PAN doesn't specify a minimum Ethernet cable length for HA, interface, or management ports. Your plan to use Cat6 UTP cables is solid. Cat5e or Cat6 are both recommended for Gigabit links.

That said, ultra-short cables (under ~1ft / 0.3m) can sometimes cause minor signal reflection or strain issues due to tight bends. It’s not a problem for modern gear, but if space allows, going with 1ft–3ft cables is a safer best practice. So your planned lengths (6" for HA, 2ft for other ports) should be fine as long as the cables are high-quality and not sharply bent.

As far as cabling for HA, If your HA ports (HA1 / HA2) are directly connected between the two firewalls, it is recommended to use crossover. If they're not directly connected and through a switch, use a standard straight-through cable.

Re: PA-820: Cable Type/Lengths and HA Port Questions

J.Logan — Fri, 10 Oct 2025 18:11:56 GMT

Understood, thanks.

I'm curious why it is recommended to have a crossover cable. I found the cables we are using and have been for some time are not crossover and go directly from one firewall dedicated HA ports to the other firewall dedicated HA ports.

Re: PA-820: Cable Type/Lengths and HA Port Questions

JayGolf — Fri, 10 Oct 2025 23:34:49 GMT

Hi @J.Logan ,

Great question! I've always wondered that myself. I haven’t gotten an official word on this, but I personally believe the recommendation mainly comes from legacy best practices. Maybe sort of a "CYA" measure in case auto-MDI/MDI-X doesn’t behave as expected.