TCPDump Errors and Solutions

Top 20 tcpdump Errors and Solutions

#	Error Message	Explanation	How to Resolve
1	eth0: You don't have permission to capture on that device	User doesn't have permission to access the network interface.	Run with `sudo` or add user to `tcpdump` group (if supported).
2	Can't open device eth0: No such device exists	Interface name is incorrect or missing.	Check with `ip link` or `ifconfig` for the correct name.
3	syntax error	Invalid BPF filter expression.	Check syntax. Use quotes and review `man tcpdump`.
4	pcap_loop: bogus savefile header	The .pcap file is corrupted or in the wrong format.	Try opening in Wireshark or re-capture the file.
5	truncated dump file; tried to read 24, only got 0	Partial or incomplete capture file.	Re-acquire the file or check disk issues.
6	unknown protocol link type	Unknown or unsupported link layer type.	Update tcpdump/libpcap or try with Wireshark.
7	pcap_set_buffer_size: Cannot allocate memory	Buffer size too large or system is low on memory.	Reduce size using `-B` or increase system limits.
8	error reading from file: Bad file descriptor	The capture file handle is invalid or closed.	Ensure the file exists and restart the read.
9	packet printing is not supported for link type 147	The file uses a link type tcpdump doesn't support.	Update tcpdump or use Wireshark for analysis.
10	listening on eth0, link-type EN10MB (Ethernet), snapshot length 262144 bytes	This is an informational message, not an error.	No action needed.
11	can't parse filter expression: syntax error	Malformed capture filter string.	Fix BPF filter syntax (e.g., remove `=` in expressions).
12	too many levels of remote in name	Invalid or overly complex interface/hostname resolution.	Use IP directly or simplify hostname configuration.
13	listening, but no packets captured	No traffic matches the filter or the interface is wrong.	Try using `-i any` or remove filters to verify.
14	can't parse capture filter: parse error	Invalid BPF filter syntax.	Simplify filters and test incrementally.
15	snoop: invalid packet capture file	Trying to read a file that isn’t in pcap format.	Check file type and ensure it's a valid capture.
16	socket: Operation not permitted	User lacks permission to create raw socket.	Run with `sudo` or assign CAP_NET_RAW capability.
17	compiled with version x of libpcap, but used with version y	tcpdump and libpcap are from different versions.	Reinstall both using the same package source.
18	file is not a pcap file	Trying to read a non-capture file.	Verify the file with `file` command and correct path.
19	Cannot open file: Permission denied	User doesn’t have read access to the file.	Change file permissions or use `sudo`.
20	warning: promiscuous mode not supported on this device	Interface does not support promiscuous mode.	Use `-p` to disable promiscuous mode or switch interface.

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Top 20 tcpdump Errors and Solutions