Common Server issues – FAQs and answers from those in the know
Google App Engine Console Down and no able to upload new versions
20 February 2026 @ 9:45 am
We get this error starting this morning, when accesing to Google App Engine Cloud Console,
Something went wrong.
There was an error while loading /appengine?project=plenion-cloud. Please try again.
It may be a browser or network issue. Go to the loading issues help page to troubleshoot the issue.
Request ID: 7831925681237543667
Also from Google Cloud CLI, we get 500 erros.
Consistent hourly NIC usage spikes
20 February 2026 @ 6:48 am
I have a hardened Debian 12 VM running on an ESXI host. It is used for file transfer and is open to the Internet.
Monitoring using Zabbix (seriously powerful open source monitoring system), I can see a consistent hourly spike of 64 kbps network utilisation received on the main interface for one minute per hour.
The server hosts a web interface allowing file uploads and downloads. I checked the nginx-access.log file but the visitors and this level of activity does not correlate.
What could be the cause of this?
How can I check if it originates internally or externally?
The server hosts a web interface allowing file uploads and downloads. I checked the nginx-access.log file but the visitors and this level of activity does not correlate.
What could be the cause of this?
How can I check if it originates internally or externally?IP Networking to local network fails unless WSL2 is started
20 February 2026 @ 2:53 am
I have a Laptop set up to connect to Internet using our corporate network, and to servers on local subnets including a local Linux server (for SVN) and our own products acting as https and ssl servers connected directly to the Laptop.
Starting in December, the laptop is unable to connect to devices on the local network using https, ssl, or svn.
I discovered that starting up a WSL2 console instantly resolves the problem and connections spring to life.
Internet access is OK, despite the problems accessing devices on the local subnetworks.
I've never had a problem accessing the locally connected hosts with ping, even though the TCP networking wasn't able to make a connection.
Before finding the WSL "fix", I was rebooting my machine frequently. Sometimes a reboot of my machine would resolve the problem, although it would re-emerge sometimes within a few minutes, sometimes after a longer time.
Any hints on how to fix this issue properly
Gmail refuses to accept email due to problems with DNS PTR record
19 February 2026 @ 3:07 pm
I use multiple IP addresses to send email. Both have a PTR record. One IP address is rejected by Gmail due to problems with the DNS PTR record.
How can I solve this problem?
relay=gmail-smtp-in.l.google.com[172.217.194.26]:25, delay=7.8, delays=5/0.11/1.4/1.2, dsn=5.7.25, status=bounced (host gmail-smtp-in.l.google.com[172.217.194.26] said: 550-5.7.25 [138.252.125.120] The IP address sending this message does not have a PTR record setup, or the corresponding forward DNS entry does not match the sending IP. As a policy, Gmail does not accept messages from IPs with missing PTR records. For more information, go to https://support.google.com/a?p=sender-guidelines-ip To learn more about Gmail requirements for bulk senders, visit https://support.google.com/a?p=sender-g
wget and curl download a specific file only partially [migrated]
18 February 2026 @ 7:10 pm
Update:
I just tried wget2 with --force-sitemap option. At least the length is shown now, but the file is still not fully loaded.
wget2 -v --force-sitemap -S -o log/wget.log -U "${UA}" "$URL" -O ${TEMP_DIR}/sitemap_${i}.xml
The Log Output
[0] Downloading 'https://example.org/wp-sitemap-posts-post-3.xml' ...
Saving '/tmp/example.org-GKJ8j1AWO4/sitemap_3.xml'
# got header 396 bytes:
:status: 200
content-type: application/xml; charset=UTF-8
content-length: 25219
date: Wed, 11 Feb 2026 10:06:41 GMT
content-encoding: gzip
server: Apache/2.4.66 (Debian)
vary: Accept-Encoding
x-cache: Hit from cloudfront
via: 1.1 a76as87df6a8s7d6fs7dad76f.cloudfront.net (CloudFront)
x-amz-cf-pop: MAD56-P4
x-amz-cf-id: ad76fas7d6f8as7d6f8asdas6df7s8d==
age: 649218
HTTP response 200 [https://example.org/wp-sitemap-posts-post-3.xml]
CloudFront
Since there is some message about Hit from cloudfront in the log, does that have
Weird behaviour of network with namespaces
18 February 2026 @ 5:49 pm
I have a Linux system with three network interfaces. Two interfaces are native (eth0, eth1) on the board and one interface is connected via a USB adapter (enu1).
Because of the application, I needed to separate them into three namespaces. The configuration was done the same way for all three interfaces (see the code below). The result is that when I PING the USB interface (enu1) from any eth interfaces, the ping works fine. But if I try to PING eth interfaces between each other the ping fails.
The routing tables are the same for all three namespaces. Can anybody clarify why there is such a difference?
The setup code:
ip netns add myns0
ip netns add myns1
ip netns add myns2
ip link set eth0 netns myns0
ip link set eth1 netns myns1
ip link set enu1 netns myns2
ip netns exec myns0 ip addr add 192.168.1.10/24 dev eth0
ip netns exec myns1 ip addr add 192.168.1.11/24 dev eth1
ip netns exec myns2 ip addr add 192.168.1.12/24 dev enu1
i
Postfix configuration with krb5
18 February 2026 @ 4:55 pm
I have Postfix on OpenOnDemand in Amazon Linux 2 AMI, working with username and password credentials in the configuration file. Email is received properly.
Now I want to implement Kerberos 5. I have Krb5 set up on the machine, using it for SSSD, and it's working. I need to implement a Kerberos authentication in Postfix.
/etc/postfix/main.cf:
relayhost = <SES URL>
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_use_tls = yes
smtp_tls_security_level = encrypt
smtp_tls_note_starttls_offer = yes
smtp_tls_CAfile = /etc/ssl/certs/ca-bundle.crt
sender_canonical_maps = hash:/etc/postfix/sender_canonical
smtp_generic_maps = hash:/etc/postfix/generic
virtual_alias_maps = ldap:/etc/postfix/ldap-aliases.cf
Also /etc/postfix/ldap-aliases.cf:
server_host = ldap://<IP>:389
search_base = DC=<domain>,DC=local
version = 3
bind
selective/partial access to sites according to IP address [closed]
18 February 2026 @ 6:12 am
DNS servers can return multiple IP addresses for a domain name. What we're observing is that some addresses yield Connection refused with a wget https://name but others accept the request. For example, this Bash script
while true ; do wget https://www.google.com 2>&1 ; done | sed -n -e 's=.*|\(.*\)|:443... connected.=\1 +=p' -e 's=.*|\(.*\)|:443... failed: Connection refused.=\1 -=p' | head -111 | sort | uniq
outputs IP addresses that refuse with a - after and those that accept the request, with a +. In our case the output is
142.251.150.119 -
142.251.151.119 -
142.251.152.119 +
142.251.153.119 -
142.251.154.119 -
142.251.155.119 +
142.251.156.119 -
142.251.157.119 -
which shows that some IP addresses always accept the request and others always refuse it.
Why would this be? Geoblocking?
Logical volume on external USB Disk not mounted during boot with error Can't lookup blockdev
17 February 2026 @ 8:51 pm
I use lvm on my raspberry pi 5 running Alpine 3.23 with internal nvme, I also have two external USB disks (WD 1Tb and 6TB). All three disks are in the same volume group vg0 with
nvme:
lv_root for /
lvol0 for /home, and
lvol1 for /var/lib
6TB HDD:
one lv named lvol2, size 930GB
1TB HDD:
empty
Problem
lvol2 on the external hdd is not mounted during boot despite being listed correctly in fstab. The other lvs mount (all three are on the nvme disk).
Workaround:
manually mount lvol2 after boot and restart affected services.
Context
fstab (relevant lines only); lvol2 has UUID c06ad240-9171-403b-8b76-71ec7d25cb46:
/dev/vg0/lv_root / ext4 rw,relatime 0 1
UUID=E8F3-9212 /boot vfat rw,re
Regular delays in sent (not received) pings
17 February 2026 @ 5:42 pm
I'm debugging a very strange issue on a Proxmox server (running on Debian 12). It is connected via a 10G link (SFP+ DAC) to a switch. Another 10G link goes to another very similar server:
SrvA -- 10G DAC --> Switch -- 10G DAC --> SrvB
10.5.1.2 10.5.0.102 10.5.8.2
When I ping SrvA from SrvB, all looks normal, with RTTs well below 1ms and a normal 1s interval. But if I flip the ping direction and ping SrvB from SrvA (as indicated by the arrows above), strange things happen. Most pings work just fine, also with RTT<1ms. But every about 20s, ping will just stall. However, it is not the normal the-response-is-delayed thing, but instead apparently a delay on the sending side, either before the request is even sent, or after the response is received and before the data is printed. After a few seconds, the line is printed with a normal RTT, with no gap in the sequences, no offending TTL, all normal. The only indication