Very slow ssh connection to OpenWrt

I'm still working on setting up squid on this router, but doing so has caused me to login to it via ssh several times and run vi to edit config files and so forth.

Strangely, my shell connection to the router has become almost intolerably slow. Sometimes 30 seconds passes between me giving vi a navigation command (like "j" or "k" to go down or up a line) and the cursor actually moving.

I looked at the processes page in LuCI and no processes are using more than 0% of CPU time.

Any suggestions on solving this sluggish ssh connection problem? I already tried rebooting just to see if it was something transient. No joy. Still slow after reboot.

Sorry, I should have added my hardware and firmware:

Linksys WRT1900ACS
LEDE Reboot 17.01.4 r3560-79f57e422d / LuCI lede-17.01 branch (git-17.290.79498-d3f0685)

Free memory: 437040 kB / 513600 kB (85%)

Probably unrelated, but why are you using such an ancient version of Lede? It probably has known security issues. Please update to the latest release in the 17.01 branch or download the latest release in the 18.06 branch. Then let's go from there :slight_smile:


Great suggestion, @Mushoz! I just haven't thought to update in a long time. Can I expect the LuCI "Backup / Restore" and "Flash new firmware image" page to preserve all my settings from version 17.01 to the latest 18.06.2?

I have a vague memory that it'll will make dnsmasq not start (no dhcp and no dns) so I would recommend you to start fresh and squid on 512Mb of RAM is probably a bad idea.


Yes it can preserve the settings, but going from 17 to 18 I recommend not to preserve them.
Take a backup of the configuration files and flash without preserving the old settings. Then reconfigure the device using the backup, paying attention to the options that might be deprecated.


If you installed "dnsmasq-full", and enabled DNSSEC, then after the update "dnsmasq" (not "full") will fail to start.

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If I recall correctly the dnsmasq user isn't created either

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I think I resolved the slow ssh connection by disabling ipV6 on the client computer that was connecting to the router.

But I'm still glad to have all the insights on upgrading from 17 to 18. Thanks everyone for those.

How do I just update to the latest release in the 17.01 branch?

You can download it from here.

That in particular was an issue for 15.05.x --> 17.01.x, but doesn't affect 17.01.x --> 18.06.x (but that doesn't imply that there wouldn't be potential pitfalls for more complex setups).

In general mvebu is a little short on entropy (it doesn't include a h/w prng, nor does it gain entropy from its wlan cards), which can slow down cryptographic services using (blocking I/O) on /dev/random.