05-18-2018 10:08 AM
I've had an Edgerouter Pro 8, v 1.8.0, running behind an AT&T managed router at our business for at least a year or two without any obvious problems. Within the last few months, the website; www.rockauto.com became slower to load and now will not load at all. Accessing the network ahead of the Edgerouter (and behind the AT&T router) with a laptop I can access the rockauto site without difficulty. I've tried clearing the DNS cache of the Edgerouter (using the CLI command: clear dns forwarding cache) and have tried modifying the MTU setting. (Lowering it below the default setting of 1500 prevents all internet traffic from flowing) I haven't found these symptoms with any other website. Nor have I made any router config changes that I can associate with the loss of the RockAuto site access. Any suggestions?
05-18-2018 02:18 PM
Version 1.8.0 does have a TCP MSS-Clamping Wizard which I selected and enabled. There wasn't much in the way of settings other than to enable it. There is a value which defaults to 1412. I did enable it but it offered no change so I disabled it. Does the CLI command script you suggested offer anything that the wizard does not? I tried clicking on the link you provided regarding the "spoiler" which I assumed would be a description of the commands. It led to a page which seemed to cover several posts/topics. I did a search on that page of mss-clamping but was offered no results. (BTW, thank you for the quick reply you offered)
05-18-2018 09:59 PM
You only mentioned MTU, not mss-clamp in opening post.
In spoiler, I only entered txt commands no link
Some sites not opening is commonly caused by MTU limitation somewhere in the path, and ICMP being blocked.
mssclamp is the way around it.
When you did use the wizard, make sure you enabled it on proper interface type. Example: If you don't have pppoe, enabling it on pppoe only has no effect at all.
1452 is my default, 1412 is even playing extra save
Also, try traceroute to www.rockauto.com to see if packets get stuck half-way
05-19-2018 06:49 AM