Networking - Spheron1

September 24, 2018

ProCurve SSH – no matching cipher found

I recently ran into a strange problem where I suddenly couldn’t SSH to any of our HPE ProCurve 2800 series (2824, 2848) devices from either macOS or Linux. I’m still not really sure what started this as OpenSSH definitely hasn’t been updated recently on the Linux client device at the very least, so I don’t see any reason for the...

HP ProCurve Comments: 0

June 25, 2016

CSF bugs and updates

ConfigServer Security and Firewall (CSF) is a great program for managing iptables/netfilter firewall rules on Linux servers and performing automated blocks based on various things such as brute force login attempts (check it out at http://www.configserver.com/cp/csf.html) and I really shouldn’t complain given that it’s free, but sometimes I really do wonder if ConfigServer/Way to the Web actually do any testing...

Firewalls/Security Comments: 0

November 12, 2015

Cumulus attacks on Juniper (again)

I have a lot of time for Cumulus Networks – I think they’re doing some very cool and unique things with their Cumulus Linux operating system for switches and they genuinely have something different to offer, but when they publish blog posts like their one today (https://cumulusnetworks.com/blog/junipers-second-run-up-the-open-networking-mountain/) I lose a lot of respect for them. This seems to be nothing...

General/Juniper Comments: 0

October 19, 2015

Upgrading to Junos 12.3 from before 10.4R2 on Juniper EX

In the release notes for Junos 12.3 (http://www.juniper.net/techpubs/en_US/junos12.3/information-products/topic-collections/release-notes/12.3/topic-69605.html#pre-resilient-dual-root-upgrade-ex) on Juniper EX series switches, it says: Upgrading from Junos OS Release 10.4R2 or Earlier To upgrade to Junos OS Release 12.3 from Junos OS Release 10.4R2 or earlier, first upgrade to Junos OS Release 11.4 by following the instructions in the Junos OS Release 11.4 release notes. See Upgrading from Junos...

Juniper Comments: 0

May 2, 2012

4GB of RAM on a Juniper J-Series router (J6350)

Officially the Juniper J-series routers such as the J6350 only supports a maximum 2GB of RAM. The J6350 comes with 1GB of RAM installed and if you want to add more then you have to buy your RAM from Juniper at inflated prices, however as the J-series are standard x86 machines with Netburst era Celeron and Pentium 4 processors you...

Juniper Comments: 0

June 5, 2011

Fortinet FortiOS firmware upgrade – Upload file is too big or invalid

If you receive an “Upload file is too big or invalid” error message when trying to upload a new FortiOS image to your Fortinet device via the web interface, then the first thing to try is giving the device a quick reboot in order to free up memory to hold the uploaded copy of the firmware image. If this doesn’t...

Fortinet Comments: 0

April 28, 2011

RouterOS slow learning BGP routes with Winbox open

After banging my head against a wall waiting for a RouterOS powered router to re-learn the 330,000 routes that currently make up the global routing table, I was surprised to find that seemingly Winbox slows the learning of BGP routes to a crawl. Closing Winbox allowed the router to process the entire global routing table in the normal minute or...

Mikrotik RouterOS Comments: 0

March 26, 2011

Fortinet SSL VPN interface limitations

There seem to be some interface related limitations with the SSL VPN implementation on Fortinet’s FortiGate firewall devices which prevent you from connecting to the Fortinet SSL VPN on the IP address of an interface other than the one which your traffic enters the firewall on. In other words, even with the appropriate rules configured in the firewall policy to...

Fortinet Comments: 0

November 3, 2010

Cisco DHCP snooping with a Cisco DHCP relay (ip helper) and DHCP option-82

By default, the Cisco DHCP snooping code on the Cisco Catalyst switches inserts option-82 into the DHCP packet but sets giaddr to 0.0.0.0, which causes the Cisco DHCP relay (ip helper) to drop all DHCP packets from a Cisco switch configured with DHCP snooping. To work around this, you can either disable the insertion of Option-82 on the switch performing...

Cisco Comments: 0

July 4, 2010

SSH on a HP ProCurve

By default HP ProCurve devices (like most switches) use telnet and TFTP (Trivial File Transfer Protocol) for management access, firmware upgrades and config backups. As these are both unencrypted protocols, it is a good idea to switch to using SSH and SCP/SFTP in order to secure your management access and all important configuration, which you can do with the following...